Effect:
Have two audience members cooperate (or even one), give the audience a set of playing cards of prophecy. Ask the other audience to say their favorite number and mark, and the other audience member is free to say their favorite number between 1 and 52. And when you look at the prophecy playing cards, you can flip through as many numbers as the audience has chosen, and there is a card with the number and mark chosen by the other spectator! It is very strange.