What are some tasks I can assign my "busy" guests who can't sit still?

Depends on the crowd, but I have asked guests to arrange crudites on a platter and serve them, take drink orders and make drinks, put finishing touches on the table, plate salads and set them out, fill water glasses. Definitely am not open to having anyone "join" me in the kitchen!

Now, how to discourage guests from stacking their finished plates at the table (gasp!) or carrying plates back into the kitchen, typically piling them in my way, when I am scrambling to get the dessert or next course ready?

I have been known to ask guests to do flowers. I usually have already pre- cut them very low and I have the small vases out, for 3 or 4 small bouquets way below eye level. Then the helpful guests can arrange the flower vases and candles on the table to their liking. Or if they bring flowers, I will ask them to do their thing. I'll ask them to put serving utensils alongside or on all the dishes, and keep track of wine. We have a small circular bar sink and an area that can become a makeshift bar. I bartended for years, and love it when guests want that job. And I also love to use the "just sit there and look pretty" line! OH, how many nuts have I burned to my total embarrassment. Now I toast my nuts in advance, always. And even then I manage to burn them.

I agree with all the comments about opening and pouring wine. And serving hors d'oevres. I also will ask them to select and be in charge of music, and to let other guests in and steer them to where the coats are being placed. My kitchen is quite small as well, so not much room for helping hands, but i like having friends lurk in the doorway and chat (as long as I'm not doing anything too critical, like toasting bread or nuts!)

I usually press them into: napkin folding (the fancy way, give them printed directions), writing out and decorating place cards for the guests (I have markers, glitter, glue, holiday-themed items such as leaves or little pumpkins on hand, particularly good for kids, can you tell I used to be an elementary school teacher?) securing the candles into the candlesticks and lighting them; wiping smudge marks off the good crystal; ricing the potatoes; bartending, uncorking the wine, walking the dog, and some other stuff I can't think of right now.

Thats a tough one, short of chopping wood or plucking the turkey I rarely ask my guests to do anything but if they are antsy they can uncork the wine, keep an eye on everyone's glasses to make sure they have something to drink, help set the table, occasionally stir something on the stove if it needs stirring, if they like to play bartender and are good at it they can mix drinks, occasionally if they offer they can take my dogs outside to relieve themselves while i am busy in the kitchen.

My kitchen is small, so too many cooks in there means that we will likely be bumping elbows and getting in each other's way. But during a dinner party, if guests want to pitch in, I have them help bring serving dishes from the kitchen out to the table or alternatively help plate the food if it's that kind of a party. I've also asked guests to pour or repour beverages, slice bread, or check on the children and make sure that they are happy and engaged. If things are frantic in the kitchen and I have a guest who I know is a good cook and who knows his/her way around my kitchen, I have been known to ask him/her to help chop herbs/vegetables and to do last minute cooking (such as making a sauce or gravy whisking together a salad dressing, or slicing a roast). But I am never, ever comfortable asking friends to clean up the kitchen or to do the dishes!

Setting out dishes usually works. If chairs need to be moved into the dining area, ask them to do that. Send them after any rambunctious children to get their hands washed. Also just give them a bench to the side in the kitchen and ask them to keep you entertained as you finish things up. Sometimes they'll sit still if their mouths can move!

I love to turn some tasks over to someone who genuinely wants to help. That way, I can keep a better eye on the kitchen. Opening wine, refilling glasses, mixing drinks, replenishing hors d'oeuvres plates, lighting candles, even stirring something on the stove that needs not stick or burn. It helps me avoid "oh s***" moments.

I usually ask guests to open/pour wine. Sometimes I ask them to set out dishes of appetizers. Depending on the friends, I often say, "honey, just sit there and look pretty."

chop wood for the fire place, shovel the snow off the driveway, pluck the turkey, or crack walnuts

If you want to keep your guests out of the kitchen, then things like filling water glasses, opening wine, and other last minute tasks around the dinner table are great. If you need or want help in the kitchen, things like chopping herbs for garnish or transferring food to serving dishes are a big help.

CLEANING!!!