Very much relevant to anybody who found this interesting: http://www.amazon.com/Godel-Escher-Bach-Eternal-Golden/dp/04...
I found it in a used bookstore for $5 once, totally by accident. It's probably the best nonfiction book I've ever started (I unfortunately never bothered to finish, which isn't so good. It's still in my backpack in case I ever get stuck anywhere...).