If I gave a real answer to that question, I'd get thrown out of the room ;-).

I remember reading about someone wanting to hire a mechanical engineer. Candidate came in, was given a blank sheet of paper and a pen, and 60 seconds to draw a picture of a working bicycle. Candidate drew a good picture, was hired on the spot, has been with the company or project or whatever it was ever since, 20+ years now.

Maybe someone else here remembers who or where that was. I came across the story fairly recently and the interview question was the part that stayed with me.