My favorite job interview question right now is:
What's the one thing that you believe to be true, but nobody else agrees with you?
I find this question fascinating because:
Identifies innovators. Most innovators have contrarian view points.
Demonstrates courage. It can be embarrassing to state a contrarian and potentially far-fetched point of view with a stranger, the interviewer. To do so demonstrates the candidates comfort with him or herself.
Exemplifies persuasion. It's not enough for one to say they believe that the sky is purple. To claim that belief requires evidence, facts and logic.