Levitt and Dubner field questions from the public and hold forth on everything from dating strategies and rock-and-roll accordion music to whether different nations have different economic identities. Oh, and also: is it worthwhile to vote?

Having already amassed an eventful resume -- the Clinton White House, the Department of Justice, and Bertelsmann -- Joel I. Klein spent the past eight years at chancellor of the biggest school system in the country. So what'd he learn?