Card to envelope.
A spectator gets the chance to perform his own magic trick. He genuinely freely selects any card and a sticker with his initials on is attached to the card's face. The card is then slipped into a pay envelope which has his initials added to the flap and address side to prevent it being switched out.
With a snap of his fingers, the spectator is going to attempt to make his signed card jump from the envelope and back into the deck's centre. However, after a couple of tries, nothing appears to have happened.
However, on removing the card from the initialled envelope it is seen to have changed to a blank card with the words 'your card' written on it! So where's the selection? A second sealed envelope is removed from the performer's pocket, and on cutting it open the signed selection is found inside.
No palming, no sleight of hand, this is strong, easy to do magic incorporating a cunning method.