A competitor who has come up with a different approach to the interviewing challenge is http://codeeval.com/
Their approach is different/beyond watching the candidate code.
(I am not affiliated with them in any way.)
Their approach is different/beyond watching the candidate code.
(I am not affiliated with them in any way.)
I always wanted to make my own challenges that would have to be automatically solved by potential candidates, and here it is! Glad someone else did this already.
Edit: I see codio.com does this as well