In a bit of a sequel to Proust Was a Neuroscientist, Jonah Lehrer talks to Teller (of Penn and Teller) and learns how the tricks that magicians do can be explained by neuroscience.
Our brains don't see everything -- the world is too big, too full of stimuli. So the brain takes shortcuts, constructing a picture of reality with relatively simple algorithms for what things are supposed to look like. Magicians capitalize on those rules. "Every time you perform a magic trick, you're engaging in experimental psychology," Teller says. "If the audience asks, 'How the hell did he do that?' then the experiment was successful. I've exploited the efficiencies of your mind."