According to College Party Guru's site, ABC parties, Kegs & Eggs, Hawaiian Luau, Garden of Eden, Retro 80's and Paint Parties are all popular. Make you sure suggest some attire to guests, and provide a few decorations to reinforce the theme.
If certain food items are related, have those on-hand as well. An ABC party requires guests to wear Anything But Clothes, so bubble wrap, boxes and sheets are all fair game. Kegs & Eggs has a breakfast theme with pancakes, sausage and bacon. Hawaiian Luau can have floral patterned shirts, straw hats and leis. Make sure your guests don't don offensive attire or culturally misappropriate other people's heritage.