If you enjoy this kind of puzzle "The C Puzzle Book" if full of them with a clear explanation: http://www.amazon.com/Puzzle-Book-Alan-R-Feuer/dp/0201604612

It's a funny little book that can keep you busy during compilation time.

And the "C Reference Manual" (http://www.careferencemanual.com/) is the best, up-to-date reference to understand how this small language can be abused.