Starfighter is new, but there are (at least?) two members coming from Matasano who used the crypto challenges (cryptopals.com) as a hiring tool in the past.

If you haven't tried the cryptopals challenges, they're basically coding exercises to illustrate common crypto problems and weaknesses. While giving the people maintaing the challenges concrete, comparable coding samples to see how people tackle non-standard coding problems.

It will be interesting to how this evolves, I found the other challenges interesting in that even if the participant wasn't interested in job hunting / didn't make the cut they still walked away learning something.