Want a linguistic challenge?

There is an annual International Linguistics Olympiad, and they are kind enough to share their problems with the public (once they've been used, that is). If you're up for a challenge, you can head over to their website and start with the sample problems and then move up to the archived problems. There are some neat data sets you can work on--I'm tempted to put a whiteboard in the hallway with a problem written on it Good Will Hunting style.