RE: Hiring Developers: You're Doing It Wrong
"In the end, the interviewer always makes a personal and deeply subjective decision, I'm merely suggesting [that we do the interview in] a way that delivers more relevant information for that purpose."
"I'm not saying that a good programmer should not have a life. But I do believe that a certain amount of enthusiasm for programming is called for... I would, however, consider the lack of any hobby projects a warning sign for _some_ development jobs."
via: Hiring Developers: You're Doing It Wrong
There is a place for purely "let's see how geeky you can get" interviews, of which Dave Donaldson (http://arcware.net/) is a master. But I don't ask the potential employee to whiteboard algorithms or tell me details of garbage collection. I'd rather not focus on what they know, but rather their potential. I try to figure out what they like, if they would be a good fit for the team, it they're a budding rock star dev, but most importantly I look for the passion - do they get excited about this stuff? Would they do it for free?