Sluts and dinosaurs
Sluts and robots
Pirates and dirty pirate hookers
Anything but clothes (make clothes out of unusual items)
Wear white, black out
Rubik's Cube Party - wear different colors, at the end of the night the goal is to be wearing the same color
No pants party
Death bowl - everyone who walks into the party pours one drink of their choice into a giant tub as people continuously drink out of it. It gets more and more alcoholic as the night goes on and fucks you up.
Graffiti/blacklight party - wear white, get a shitload of blacklights, draw on each other with hilighters.