Need a good main dish recipe for office party.?

My office has decided to do a halloween party type event, with a pot-luck lunch. Each person was asked to sign up to bring something. Looking over the list, I see lots of people bring desserts and appetizer type foods, but pretty much nothing else. I would like to bring a good main dish, but am unsure of what would carry well (since I may not have a way to keep it very hot) and feed 20-30 people that wont break the bank in the process. Any ideas?