Larry's Favorite by Larry Jennings
Larry always had a deck of cards with him, and if anyone ever asked to see an effect, this was the very first thing Larry would perform for him. His reasoning was this… all laymen think every card effect begins with a selection, so Larry wanted to scratch that itch right away. After they return the card to the deck, Larry immediately asks someone to name a number and boom - he quickly cuts a packet from the deck. Counting the cards, it is the exact number just named, and the final card is… the selection!
In Larry’s mind, this proves beyond a shadow of a doubt, that you can find whatever card someone selects. After that, he would move on to other effects, but the first thing he always did was to instantly find a selected card, because as far as laymen are concerned, that’s the Prime effect in all of card magic.
Originally on "Easy to Master Card Miracles Vol. 8" DVD
Larry's Favorite card trick explained