Check out my website of logic puzzles, brainteasers and riddles:
flooble :: perplexus
The site is a great place to give your brain a workout after all that mind-numbing HTML/PHP coding. Meet people, work together to figure out solutions to puzzles, argue your point, or just plain old lurk.
With almost 500 puzzles in 20 categories, ranging from simple word tricks to advanced math, you're sure to find something to perplex you.