Free Lunch, Part II
The founders of Become.com told job applicants to spend 40 hours trying to come up with a better search engine than Google. 100 applicants took up the challenge.
The interesting thing is that in the original article, the CEO commented that "Many of the concepts that came out of that process ended up in the Become.com algorithm."
After an instant firestorm of blogger criticism from notables such as Om Malik, who decried this as exploitation, the founders of Become.com quickly claimed that none of the code went into the Become.com codebase.
As far as I'm concerned, that's not exploitation, that's entrepreneurship. No one put a gun to the job applicants' heads and forced them to invest their time. Why not get something useful out of the job interview process, rather than having them work on meaningless problems?