There's actually a book that covers some of the old contest winners:

Obfuscated C And Other Mysteries by Don Libes

http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/d...

The Don Libes book, Obfuscated C and Other Mysteries [0], is a fantastic programming book, among my top ten. I think it's out of print, but Amazon has used copies.

[0] http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/d...