summertime, and the livin' is...boring

In the weeks since I got off of school, I have been the only one at home (with the exeption of the dog), with nothing to do but clean. I am in serious need of some good, cheap (free is better) fun. I know of the obvious ones being the zoo, science center, the park, shakespeare in the park, and the movies. Is there anyhting out there that I am missing? What do y'all do for fun? Any secret venues? Let me know!