Fund Raisers!!?

You could have a silent auction. Get donated items from teachers, parents, friends, local businesses etc., Take a detailed picture of each item, much like e-bay does. Display pictures with bidding forms on tables or walls in an approved area for an appropriate amount of time. Bidders list their name and other pertinent identifying information with the amount of their bid. Tally the bids at the end of the auction, notify the winners, collect the money, deliver the item, have fun at the prom.