NASCAR races, of course! Wife and I have been to 14 different tracks now; 12 of which we used the RV for. Most times it's for a very long weekend with lots of races and other side events to take in, and there are always a lot of "interesting" people to meet. Usually expensive though, especially since you're paying for a spot in a vacant field and within arms-length of your neighbors. Generators run all night even though it's almost always against the rules, but at least that drowns out the noise of countless all-night parties.
Did I mention it's a lot of fun?