Kaggle is a series of "big data" (as far as I can see, widely interpretted-- basically problems which are so large classical computation attacks won't work) with real money prizes. Needless to say, I'm not aiming to really compete.

Packing Santa's Sleigh

See the official description. We're thinking about this, a little, in the Python discussion group, an informal staff and student meeting convened by Rob Sturman.

This is a 3D problem, but an easier version would be to attack the analogous 2D problem. Here are some relevant links.