The Pass aka The Shift and Classic Pass
The spectator places a card in the middle of the deck, unknown by the spectator, the magician moves the card to the top of the deck.
How It's Done
Have the spectator select a card, hold half of the deck with your left hand and have the spectator put their card on top. Place the other half of the deck on top of this with your right hand, but keep a pinky break with your left pinky. In one motion you grab the bottom portion of the deck with your right hand and top portion of the deck with your left and reverse the positions, using your hands and the new top of the deck to hide the switch.