Audiobooks.net is offering over 460 free audio books to anybody who wants to download them. I have a rather lengthy road trip coming up soon, so hopefully I'll be able to put some of these to good use and not go mad with boredom. Not to be confused with going mad with anger, which is actually kind of fun as long as there are nearby objects you can punch.
You have to sign up for a free account, but there's no software to download. Just log in and start downloading whatever you want.