I like this one.

What he asks: If I stood you next to a skyscraper and gave you a barometer, how could you figure out how tall the building was?

Why: The answer: well, there really isn't one. Baden just wants to see how creative people are. According to company lore, one interviewee responded that he'd find the building's janitor and then offer the janitor the barometer -- in exchange for information about the building's height.