Dinner Dilemma

Our agency doesn't like spending money on frills, which I like. So they ask parents in the class to bring their own dinner. The classes are long and intense, and most people come there straight from their work, so dinner is fairly important. We've volunteered to bring dinner for next week's class.

Last week it was pizza, before that ham sandwiches, and before that pasta salad. I really want to cook my own food, and also cook something that will impress the class. It's not like our future children will depend on it, but I just love cooking and can get pretty worked up about it. The challenges are:

1) The floor has new carpet. Nothing crumbly like cornbread or with a lot of juices (that rules out my collard greens). Rice might be OK.
2) It has to be acceptable to a wide array of people. Nothing too spicy, and I probably should have a vegetarian dish. Keep it simple, Americana or southern: no kielbasa or kimchi.
3) No deli-wrap-roll-type foods. I hate those. Does anyone like them? They're easy to eat, but people are always mistrustful of them, since you can't tell what's inside.
4) Something that doesn't have to be served warm. I'll be cooking it the morning of the class, so it will need to be good served lukewarm or cold.

This is going to be tough.