Regular reader, Dr. Mark, sent a link to this video. I thank him most whole-heartedly.
It features the late Milton Friedman engaged in a debate with a young man identified as Michael Moore - yes, that Michael Moore. I haven't seen anything to confirm that part, but Dr. Friedman's explanation to the young man (whoever he was) is great. I'm sure this will stir things up in an economics class, or even an ethics class.