[9999]

I haven't spent much time with Project Euler, but I can see how puzzles and riddles could be a more enticing introduction to programming for a lot of people. I'm not particularly averse to learning via giant tomes on programming or in a classroom. Then again, I think I found that I learned a lot more about problem solving in Python (and had way more fun) doing the Python challenge (http://www.pythonchallenge.com/) than I did following the examples in Dive into Python.

[shurane]

As a fan of David Münnich's notpr0n, I must say that the pythonchallenge website looks like a really cool spinoff and seems more approachable than Project Euler.

Edit: Not to mention you're not restricted to using Python, just like Project Euler. What's not to like?