Free entertainment

I've been thinking about free (to cheap) local things to do, and started to come up with lots of lists and urls. Any other ideas or suggestions would be very much appreciated. Of course, in these lean funding times, any of the nonprofits listed here would be very happy if you decide to make a contribution.
I wish there were nested lj-cuts.

( public libraries )

( author talks )

( movies )

( museums )

( colleges and universities )

( walks )

( summer stuff )

( annual events )