A large model of our original Rainbow Chips, using huge chips 3 inch in diameter (the deck of cards is for comparison only - to show you the size!) with pictures that will appeal to the younger members in your audience.
In effect you show two chips with four monkeys on both sides of each chip. Rub them together, and the monkey pictures change to four different pictures as illustrated in the large picture (GIF). Complete with instructions, very easy to do.