You may be an experienced dinner-party host, but having a hands-on workshop or 'work bee' has different aspects.

The general outlines are the same:
- make sure everyone has directions, including the date, time, place, and what to bring or wear.
- once people are there, make sure they have what they need.
- be clear about the plan, follow it if possible, and be clear about any changes if necessary.

One-Day Events:

If you are hosting a group to work on a project for a single afternoon or a full day, your main jobs are:
1) Keep things interesting
2) Keep people healthy and refreshed
3) Hold space for guest contributions.

1) Keep things interesting:
     Choice of Work:  If you are hosting a group to help on your pet project, try to save the more interesting, fun, or easy parts for the group.  This means knowing your friends' interests, or describing the project accurately so people know what to expect when they decide to come.  For example, fastidious friends might prefer to shell peas or make jam together (tedious but tidy work, that allows for a lot of talking).  Science fans might enjoy turning compost if you provide a magnifying glass and jars for capturing the best bugs.  You can offer a choice of several kinds of work, and let the guests feel they have 'gotten off easy' by choosing their favorite.
     Guest Talents: If a participant has a special skill, we often invite them to share it during a demonstration.  You can also invite specific guests to create interest - for example, a musician friend to play while everyone else works, turning a chore into a 'dance.' 
     Big Jobs:  The other traditional time to call in friends is for the part of the job that is literally too hard for you to do alone - like a barn-raising or cider-pressing party.  Being genuinely useful is a good feeling, and the kind of friends who enjoy work-parties tend to enjoy being useful - but be sure to feed them well, and plan on reciprocating on someone else's big project.  Don't plan too much into the day; and prepare ahead of time by clearing paths, emptying trucks, etc.
    Fun: Turn on some music; introduce people with compliments or by noting something they may have in common; serve your family's secret recipe iced tea or barbecue sauce.  Gracious hospitality transforms the work into a genuine 'party.'

2) Keep people healthy and refreshed:
     Site Safety: Make sure the site is as safe as you can make it.  Have appropriate protective gear such as gloves, and basic first aid materials (such as cleanup and bandages materials) on hand if there is any risk of injury.  People can injure themselves in surprising ways if they are nervous, tired, or over-excited; do what you can to help people stay relaxed and enjoy the day. 
     Water: As a minimum, make sure you have plenty of clean water (or other healthy beverages) on hand so that people stay hydrated (it's especially easy to forget this while doing fun, unaccustomed work).  For long outdoor days, consider
 - set up a permanent 'hydration station' right near the work;
 - offer pens to label personal water bottles or canteens that people can use all day; or
 - have a 'water fairy' (a volunteer who makes a point to go around and offer others water at regular intervals). 
 - If you allow beer or alcohol, even BYO, consider disappearing it at first 'to keep it cool', and bring it out again after the dangerous part of the work is finished.
     Food: Friends are much more willing to help if you feed them well - pizza and beer being the traditional rewards for moving day.  Plan ahead so you don't need to be in the kitchen all day: crockpot chili or stew; build-your-own burritos with pre-cooked ingredients; prepared tea sandwiches for light work; or order out.  The meal is what puts the 'party' in 'work party,' so make sure you feed your guests the best. 
     Facilities:  Most homes have great sanitary facilities (toilet/washroom), but make sure you are ready to provide these for people with muddy feet.  An outhouse or port-o-potty can be acceptable; but peeing behind a bush doesn't work as well with 20 people wandering the same patch of woods on a short break.  Likewise, you may want an outdoor hand-wash station for mealtimes to save grit and grime down the indoor sinks.
     Timing: Make sure people have what they need to start work (a drink or snack may be appreciated, but a heavy meal may delay the start of work).  Also offer food at breaks/stopping points after accomplishment, or when people start to get tired or cross -  either in the middle of the day, or at the end of a shorter work session.
     Pot-Luck:  If it's polite and practical in your group, you can ask people to bring pot-luck food.  Remember that preparing food takes time for everyone, so pot-luck is most practical during short, weekend events.  Weekday potlucks tend to feature a lot of deli plates and chips.

3) Hold space for guest contributions.
This means being prepared, and then taking a back seat to your guests. 
   Preparation and Communication: Have project materials, tools, and space laid out all ready to go.  Know your backup plan in case of weird weather.  Make sure guests know what they are expected to bring - this can include tools, gloves, even steel-toed boots or life-jackets - just be clear well ahead of time.  If you are hosting a potluck, prepare a hearty main dish (in case everyone else brings dessert) but don't create a 4-course meal that excludes other contributions.  Consider coordinating contributions, so that everyone knows what to bring so it all comes together. 
    Minimal Management: Once the party is underway, you will need to let people do a certain amount of their own work and problem-solving without micro-managing.  Be clear about expectations beforehand, and make a brief group announcement if any change of plans or clarification is needed.
     Social Time: One of the best things about getting together for a project, is getting to spend time with great people.  Hosts don't need to entertain or control the schedule all day.  Instead, try to allow time for casual conversation and relaxed teamwork.  Just as at a dinner party, introduce people to each other by mentioning something they have in common, or steer the conversation toward topics that everyone can enjoy and participate in.  When your guests enjoy each other, they leave with a good impression of their host.
    Work as Fun:  Unlike a dinner party, a work party can feature talents other than conversation.  Let your handy friends show off a little.  Set up teams of people who will enjoy working together.  Let things get a little messy, or have a contest, if it seems appropriate, but avoid embarrassing any of your guests.

Multi-Day Workshops:

The responsibilities of the host for a multi-day workshop include all the above, plus a few additional considerations.  Think about how you plan for a family visit or weekend camping trip, and realistically scale these up to a larger group. 

Sleep: Guests will need safe places to sleep - this can mean camping, home-stays, nearby hostel or hotels, or a temporary hayloft dorm.  The host does not need to provide on-site camping, but it's worth considering for out-of-state guests, especially if the nearest beds are hours away.  Be clear about what facilities are offered / included, and allow guests to fend for themselves (with local recommendations if appropriate).  On-site accommodation, if convenient, does help keep a workshop on schedule.

Food: Hosting a multi-day event means guests have little time to prepare their own food.  Our preference is for the workshop to include well-balanced meals with enough variety to suit most guests dietary needs.  If most participants are local, there may be more options for sack lunches, or we can end early enough for everyone to go into 'town' for restaurants or deli shopping.  Pot lucks generally don't work well for multi-day events, as nobody has time to cook beyond the first day.
- Hearty Portions: Expect most people to eat more at a hands-on event than they do at home; plan to have leftovers rather than run short.  An experienced camper, parent, or caterer can usually plan ahead for several minimal-fuss meals; if you have never cooked for more than 4 people, consider finding a reliable helper who can make emergency pizza runs if needed. (A sample menu from experienced outdoor hosts is provided in the left sidebar.)
- Meal schedule: As a general rule, set breakfast, lunch, and dinner at the same times every day, about 4 hours apart, with an afternoon 'tea' or midnight snack if needed.  When food and water are constantly available, people stay healthier and work harder. 
- Kitchen Duties: Make sure the person assigned to cook has time to do so (delegate or prepare ahead if you plan to host, build, AND cook), and assign a couple of cheerful people to do dishes immediately after every meal.  Kitchen help and dish duty can rotate between participants, or be hired out to outside help.  If you choose to have everyone use and wash their own dish at mealtimes, allow extra time and water for inefficiencies.

Site Safety:  When hosting people overnight, darkness can increase the risk of casual hazards such as ditches or construction debris. 
- Clear Site: Clear the paths ahead of time:  a space for evening entertainment, and clear access from sleeping to toilet facilities.  At the end of each work day, make sure tools are put away and there are no hazards left on the ground. 
 - Orientation: Let people get reasonably familiar with the paths and hazards by daylight before turning them loose at night, or offer flashlights or a guide if needed.  Camp lanterns or low-powered LEDs can mark the host's doorway, path crossing, or outhouse.

Facilities:
 - Toilets/wash stations should be close to the worksite, food areas, and to any overnight camping.A 'comfort station' suited to the nature of the activities also helps people feel at home: band-aids, sunscreen, toothpaste; hand wash with soap; lotion for clay-dried skin, or GoJo if working with lime/cement/solvents.
- Personal Space: During extended workshops, people may need time and space to process new ideas or handle their private lives.  A shorter workday allows time for self-care and family obligations.  'Quiet' or private areas, and a public area, can help mitigate any personality conflicts. 
 - Bathing: In addition to basic toilets, in a longer workshop guests may need to bathe or shower.  There may be a queue for bathrooms in the morning and at every break.  If you don't have bathing facilities on site, consider providing directions to a local swimming hole or pool (all public pools have showers, yes?).  An on-site shower can also be useful for first aid (such as removing poison oak or poison ivy oils, or cooling a person with heat stroke). 
 - Dry Clothes: Most people don't need to do laundry during a long weekend, but it may be useful to have a place for drying wet gear after a rainy workday.

Health:  In a large group doing unaccustomed activity, you can anticipate at least one minor health problem over a multi-day workshop.  This may be as simple as blisters or abrasions, or as serious as a diabetic emergency or severe allergic reaction.  Check with participants if they have medical conditions (or medical training) that might become relevant during the activity.  Most hosts prefer to have all guests sign a waiver upon arrival, to limit liability.  In case of an emergency, defer to the best-trained medic on site, and call 911 for immediate help.  The emergency medical service can give good advice regardless of the severity of injury, and the injured person can refuse to be transported if they are comfortable handling the incident on site. 
   A basic first aid kit might include
- bandages,
- antiseptic wipes or soap;
- antibiotic ointment or salve
- a cold pack,
- tape / plastic wrap / Ace bandages for sprains or splinting, and
- non-latex gloves; CPR mask if trained
- spill-wipes (paper towels).  
- good tweezers, 
- burn cream or aloe vera
- maybe some chewable Benedryl and chewable aspirin if you are outside of rapid response areas.  (helps with common allergic reactions, minor pain, and some heart conditions.)

  Experienced workshop hosts and instructors develop a good eye for hazards, and help participants maintain a clean site and healthy work habits. 
Some common, manageable hazards include:
    - dehydration
    - sharp objects on site (including glass, tools, old burn piles, building scrap)
    - over-strain or 'weekend warrior' syndrome
    - animal conflicts: nervous pets, loose farm animals, etc.
    - hygiene on primitive sites: unlabeled non-potable water, limited hand-wash, primitive toilets
    - fire danger
    - medical conditions participants may already have, such as allergies, old injuries, or a chronic conditions such as diabetes or heart disease. 

All of these hazards can be managed with participants' cooperation, and most accidents can be avoided as a result.
First-aid training is available from the Red Cross, American Heart Association, and other local groups.  Nurses, doctors, paramedics, child care providers, and firefighters are commonly required to have such training, and may know good local options or be willing to help out at an event.  Very large or remote events sometimes hire a 'site safety' or 'first-aid station' coordinator.

After Hours and Site Rules: What does the 'party' look like when the work-day is done? 
     Participants need to be able to relax, unwind, and finish processing the day's events.  Some people do this socially, others retire to mull things over in peace and quiet.  Providing enough free time for comfort and conversation, but not so much that people get bored, can be a key element of hosting a good workshop.  Generally, we allow at least a couple of hours between dinner and a full 8 hours' sleep; more if local participants may be going home and returning in the morning. 
    Site Rules: Decide ahead of time what your tolerance is for alcohol, smoking, pets, noise levels, or other recreational habits, and let participants know before arrival and during the first announcements.  Only announce policies if you are willing to follow and enforce them - hypocrisy or laxity can create a vacuum of leadership that's worse than no policy at all.  If you don't have a policy, you can still set the tone for acceptable behavior by example.  Address any problems immediately, privately if possible, and use common sense, courtesy, and firmness. 
    Entertainment:  Some hosts offer on-site or local entertainment options, such as an invitation to bring campfire songbooks, or to join a nature walk in the morning before breakfast.  Local tourist guidebooks are also fun.  Make sure there are safe paths from the entertainment areas back to sleeping quarters, and that your guests have what they need before you retire.  Ask other responsible adults to chaperone the party if needed. 
   Self-Serve: A 24-hour, tea-coffee-and-snack station does wonders for people's comfort and stamina.  Make it clear where early risers or night owls are welcome, so you can get enough sleep too.

Weather: The longer a workshop, the greater the chances of encountering unplanned weather.  Heat can be just as dangerous as cold; rain can make people colder than snow.  Include a weather update (or link) in your welcome letter, and encourage participants to bring weather protection suitable to the type of activities planned.
     For multi-day workshops, always plan to have at least one shelter big enough for the whole group to gather (ideally, this should offer shade, wind-screening, and a way to get warm; bug protection is a bonus); and plenty of clean water to help people stay both warm and cool.  (Dehydration can accelerate hypothermia as well as heat stroke.)
     Work can continue in almost any weather as long as people have suitable clothing, and good food and drink to revive them afterwards.  We play smart: no fires in a windstorm, nor outdoor work in heavy hail.  We also adjust the work schedule, or occasionally the hours, to take best advantage of the weather.  Typically we do the heaviest work in the morning (to warm up or stay cool), but may include an evening work session if the day gets so hot we need a siesta mid-day.  We try to keep sit-down sessions short and timely, but may extend indoor sessions in inclement weather.

Activity planning and Group Dynamics:
     Flexible Planning: The longer the event, the more effect the guests' group dynamic has on the pace and quality of the planned activities.  The advertised 'deliverables' in a workshop include only the basics; every workshop involves a different level of depth and variety of 'bonus' experiences.  If things go seriously off schedule, it can work well to call the group together and discuss remaining options.  Bonus activities or early dismissal is a fun choice; a lagging group may have to choose between picking up the pace, or triaging planned activities based on the time remaining. 
     Addressing Problems: Most problems are easier to solve if you maintain a no-fault correction - for example, "We have found some glass on site - thank you to X for warning us, and we now recommend wearing boots." is a lot more useful than, "Does anybody know what bozo broke a beer bottle last night?" 
   If possible, try to talk to an individual privately about any personal problems or behaviors, instead of calling them out in front of an audience. 
   If a new policy or general announcement seems in order, confirm with other staff, and then keep the announcement brief and impersonal: "I may not have made it clear that we have a policy of X; we need to stick with that standard from here out.  I will appreciate all of your help in making this happen."
      Open Opportunities: A good group facilitator brings out guests' special contributions, without sacrificing the planned 'deliverables' that everyone was promised.  The host and instructors are responsible for ensuring that everyone gets what they paid for, and that means we need to keep a reasonable handle on the crowd, kind of like an MC.  As long as this role is respected, it works very well to offer equal respect to guests' skills and experience.  We often invite an experienced participant to demonstrate a technique if it's in their specialty (for example, a mason to set some bricks, an HVAC guy to oversee the stovepipe fitting, a wild-crafting potter to show properties of local clays, a fire marshal to 'read' the smoke, or any music-lovers to set up an improvised sound system and share playlists).  We do this not only to flatter our guests, but also because it creates a richer learning environment where everyone (including ourselves) gets to learn from the widest range of experienced teachers available.

Trade and Money:
     If there is money to handle, handle it as early and briefly as possible.  Typical events sell tickets and then check them at the door, avoiding any lingering negotiations. 
   Pre-registration: Collecting a deposit or full fee with registration is helpful, as it provides a cash flow to purchase food and supplies.  And most people are more likely to honor a commitment when they have pre-paid.  Discounts for early registration may be offered.
    'At the Door': If anyone is expected to pay after arrival, make a quick announcement as early as possible stating the expected fee (or sliding scale, or voluntary donation), and who to see about it.  Have a registration list, and check people as they pay.  There should be one person who collects these fees.  Drop boxes and baskets are hard to monitor, and should be used only for optional-donation events.
     Work-trade: In some cases, a guest may negotiate to pay with work instead of money.  This works only with very clear agreements between honorable parties.  If making an agreement with a person not known to you, it's usually wise to collect the work in advance of the event.  (This can be a simple work-party to prepare the site.) 
    We don't usually advertise 'work-trade available' any more, as we tend to get more  inquiries from people who don't really want to offer the full value in work, but want something for 'free'.  If your area does include a number of hard-working but cash-poor people, you might consider a public 'wish list' that is good for discounts: parties of 4 or more who register together, a truckload of bricks, two good cooks who can alternate meals; help collecting scrap metal, tools, or earthen materials.  A full day of pre-workshop help generally pays for a full day of workshop instruction.
     Free: If the event is free, it can still be useful to announce any terms of participation at the beginning - such as goals for the time, tasks, chores, need for specific helpers to stay after, or general behavior expectations.  Among friends these may go without saying, but in a group of strangers it can be helpful to allow guests to agree to the terms of their participation in advance.