Trip ideas for a group of teenagers?

So I need to plan some kind of trip for a large group (well, the size can vary from about 20-50, depending on who wants to go). By "trip" I don't mean like a vacation to a foreign country or anything, more like a field trip. But fun.

For past trips we've gone to the movies, paint ball, corn mazes, and amusement parks.

It should also be something that costs each kid $50, at most. And it has to be interesting enough that people will WANT to pay to go.

Any ideas?