A simple un-gimmicked version of Paul Harris's legendary Strange Travellers effect!
Using a normal deck, you'll be able to achieve the following miracle. Spectator #1 mentally notes ANY card in a group of cards, and never tells anyone what it is. The packet is handed to Spectator #2, and the cards are counted to be sure there are exactly ten cards. Spectator #1 is handed a separate group of cards.
The magician makes a magic gesture, and now Spectator #2 counts the cards, only to find that one is missing! The exact card that Spectator #1 merely thought of is now in Spectator #1's OWN packet of cards!
Download the video and soon you'll be performing this astounding feat of magic!