Programming Challenges

[brokenbylaw]

This is not for you to solve a programming challenge of mine, I'm looking for some challenges, can you guys give me some ideas.

if we get some ideas it would be cool to have some people respond with some answers! i definitely will!

language specific challenges would be nice

[alienkinetics]

this site is waaay cool.

Project Euler

Very well designed.

[tossy]

Programming Challenges

[brokenbylaw]

See i like those! but i want you guys to not provide links (google does that quite nicely ) but choose some challenges you find "cool"/"good" lawl.