Experiments in Madness

I've already listened to some great books from librivox, and plan to give back to the community by reading something.  While searching for public domain books I ran across Science Fiction Radio Theater.  There doesn't seem to be a way to download the content so I could load it into my MP3 player, but listening to just a snippet of one of them, Project Mastodon, by Clifford Simak was a hoot.