Project Euler

Great problems are really hard to come by. Great problem sets are even harder. I just ran into Project Euler online. I'm really blown away. I would love to use this in one of my courses.

Project Euler is a sequence of 220 problems. The problems are designed to be an "inductive chain learning" experience for the solver. This is from the PE website:

The problems range in difficulty and for many the experience is inductive chain learning. That is, by solving one problem it will expose you to a new concept that allows you to undertake a previously inaccessible problem. So the determined participant will slowly but surely work his/her way through every problem.

Let me know if any of you are working your way through the problem set at the moment.