Just this month I discovered Joy Hakim's "The History of US" on tape from our library. It's a children's history of the United States, but I'm enjoying it as much as the kids. :-)
I've mentioned before how well audio materials work for my RBers. We've listened to all sorts of great stuff, fiction and non-fiction. Listening in the car works for us. I have 3 RBed kids, 2 of which are very kinetic, and don't hold still for long. We also live outside of town, so have to drive a fair bit. Audio books help keep us occupied (although, for longer trips I still usually have to give them hand work as well, like modeling wax or crocheting).
Let me know of any good finds you know of. I wish I had found this one years ago!