Gödel, Escher, Bach: A Mental Space Odyssey

This book is incredible (and incredibly long). Barry Ritholtz found an MIT class on it:

What do one mathematician, one artist, and one musician all have in common? Are you interested in zen Buddhism, math, fractals, logic, paradoxes, infinities, art, language, computer science, physics, music, intelligence, consciousness and unified theories? Get ready to chase me down a rabbit hole into Douglas Hofstadter’s Pulitzer Prize winning book Gödel, Escher, Bach. Lectures will be a place for crazy ideas to bounce around as we try to pace our way through this enlightening tome. You will be responsible for most of the reading as lectures will consist primarily of motivating the material and encouraging discussion. I advise everyone seriously interested to buy the book, grab on and get ready for a mind-expanding voyage into higher dimensions of recursive thinking.

And videos of the lectures are online.