Any ideas for a block party booth? read description!!!?!

Every year, our local elementary, middle, and high school throws a block party. And students participate in one way or another. My commercial design design class (fancy way of saying advanced art) has to set up a booth. Last year, our former teacher came up with face painting. This year we have only one idea: we have plain cookies and kids could decorate them. We need to raise money, and we want an idea where the people could just walk in, and go out. Any ideas on what we can do?