I like making sushi with freinds. Rolls are easy.

i know it sounds ordinary, but i heart pizza night - i ask everyone to bring a topping that's tried and true and a second topping that's adventurous. you can buy dough & cheese & sauce at trader joe's super cheap. i make my pies on cookie sheets, and you can cook two sheets at the same time - so folks get to hob nob while they're laying out boundaries for their half of the pizza. you get to try pizzas you'd never think to make and everyone's stuffed with minimal effort!

my favorite group meal, though, are empananadas.... i usually make mine peruvian style which means cooking up meat then slicing up egg then adding in raisins and it takes eons by myself.  did you know that anything you think is tasty is actually tastier in an empanada? it's true.  carmelized onions and blue cheese?  yes.  smoked salmon, cream cheese, fennel?  yes. sweet potatoes, chillies, mexican crema and mangoes?  yes.  tofu and curry?  yes. spinach, feta, olives and lemon?  yes.   the pate brisee from smitten kitchen is a winner - i omit the sugar when it's a savory filling.  

I'm a simple simpleton, and it seems like spaghetti with sauce would be easy on the elbows. Mostly involves stirring stuff and chopping some other stuff depending on how you make it. And, it is good for groups of people to nom nom nom. :)

Stir fries.

There is a ton of prep work that goes into a stir fry but the actual cook time is very short. With a few people over you could make a few different pre-planned dishes, or just have everyone cut up veggies, tempe, tofu or whatever else people want in stir fries, make different sauces, and then improvise. Regardless, doing a stir fry by yourself can feel like endless chopping while doing it with even one other person is far more enjoyable.

It doesn't take long to learn to stir fry, but do get a good carbon steel wok and season it, and expect there to be some non-so-delicious attempts at the beginning. You could also let other people attempt and learn to stir fry since you'll presumably have a small mountain of ingredients.

Risotto.

The traditional cooking method for this dish requires standing over it and stirring continuously, while gradually adding liquid, for about twenty minutes. This is a pain in the ass if you're cooking alone, but it makes an easy, fun job for someone helping you (although it takes a little elbow grease).

It's an all-purpose comfort dish with endless variations, that goes great in vegetarian meals.

Here's a basic recipe. You can substitute veggie stock for chicken. Use your imagination and add whatever ingredients you like (mushroom and lemon are popular, for example).