I've been to several 80's parties, a James Bond themed party, a Moulin Rouge themed party, zombie party, and my all time favorite, a white trash party. I love theme parties and wish people would throw more of them.

Are you encouraging your guests to come in costume or bring something like a food/drink/game that references on of the movies? If so you should give out a prize to whoever has the best. Nothing crazy expensive, just something really silly and novel. Favors are the best.