I need after prom ideas!?

My prom is really late this year, and I'm a junior guy going with a senior girl (our prom is seniors only unless you're invited by a senior). We have plans to go get pictures and dinner and such before the dance, but we don't have any ideas really about what to do afterwards! Our group is going to have an after party with drinks, and my date and I are trying to avoid that. What are some good ideas that don't involve booze or any illicit substances? Thank you!