As a correlation to this site, there is a secret programming challenge within google at: <a href="http://www.google.com/foobar/" rel="nofollow">http://www.google.com/foobar/</a><p>You have to get invited to it (via searching the correct keywords, etc. I got invited when googling about dependency injection). It is a series of programming challenges that get really difficult. But after completing them, I got a final round interview at Google, which was pretty cool.