You spread out a deck of cards face up, and ask a spectator to choose any one at all. When she has done so, ask her if she wants to change her mind. When she has finally settled on a card ( for example the nine of spades ) you announce that you absolutely knew in advance which card she would take. In fact you even told a friend.
You ask the spectator to pick up the phone and call your friend, Phil Taylor, and ask him what card she chose. When she does so, your friend Phil answers: Why you took the nine of spades, didn't you?