Split Deck - Bicycle
A deck of cards is shown to be cut in half. The cards of each half are turned face up and shown to all be different. The magician (that's you) asks a person to select a card from one half as he spreads it out face down. The selected card is placed on the table Another spectator is asked to freely select a card from the other half of the deck. This selected card is also placed on the table next to the first one. When they are turned face up, they match perfectly.
Easy to do, no skill, and no practice is needed. Works 100% of the time, everytime. Great for beginners.