Are you up to the challenge? Take the Pi Day Challenge--a series of puzzles involving logic and math. The Challenge is open now and sounds like it will be running for the next several weeks.
When I logged in, before I completed any of the puzzles, I was ranked 543 in the world. It'll be interesting how far I can make that rank improve. I'll post updates as I complete puzzles. Let me know how you do by posting a comment. Have fun!
Pi Day Challenge 2011 | Pi Day Challenge