Paul Hoffman was editor of Discover in the 1990s when for five years the magazine published a hoax each April. Many people were taken in by the April fool articles. Hoffman, an avid amateur chess player, was himself taken in recently by the "discovery" that 19-year-old Magnus Carlsen, ranked the best chess player in the world, is a second cousin to actor Matt Damon. Smart people are some of the easiest ones to fool, says Hoffman. They think they're too smart to be fooled, they've learned to believe in things that are counterintuitive and they know scientific explanations often defy everyday experience (Discover, October).