Agreed. I didn't get too far in Project Euler myself before finding other programming problems to solve. Logging in I only solved 4, apparently. Which doesn't seem right, maybe I accidentally created a second account, I've done that a few times.

The main issue was, though I have a math degree, there was no way it would appeal to most of my friends when we'd turn these sorts of things into a (mostly) friendly competition. Hacker.org hit just the right buttons to keep a few of them interested long enough to even plough through the problems they didn't enjoy just to make progress.