http://thisishell.net

http://fold.it

Solve puzzles for Science!
Foldit enables you to contribute to important scientific research by by playing a cool 3d game where you fold proteins.  Humans do a way better job of pattern matching than computers can muster (for now) and humans are great at it.  I had absolutely no idea what I was doing but the interface is so intuitive and the scoreboard makes your progress or failure easy to track in real-time that I actually found myself addicted in just a few rounds.  Enter at your own risk, this is one major potential time-suck, albeit a worthy one… for once.