Here is a very simple one. Memorize the bottom card. Easy to nonchalantly tilt the deck when explaining what youd like them to do. Then fan out the deck face down and ask them to pick a card. Then get them to place it on top. Next get them to cut the deck and put the bottom half on top which places the bottom card you've memorized to the left of their card. Now flip the deck and search for their card and reveal.