What to do as a college student in STL for the summer?

I'm going to be working as an intern for a nonprofit based in St. Louis, I'm going to be living off Delmar with one of my fraternity brothers. Does anybody know what there is to do for fun in Stl for the summer? Also how do I prevent myself from getting isolated living with just one other guy. Where is a good place to go to meet college people during the summer?