These are wonderfully fun magic tricks -- or more better described, illusions -- from Richard Wiseman, who among his other talents is a psychologist. Very often, they're under the heading of "Amazing bets you will always win." Since what he presents are more in the illusion (or even better yet, optical illusions, or simple explanations of unusual natural phenomena) than traditional, pure magic tricks, what makes these videos all the more fun is that he explains them at the end.