2 Chess boards, ten white and ten black chessmen
You have, one board and your friend the other. Divide the chessmen equally, each having five white and five black. Then while YOU look another way, your friend arranges his men on his board in any formation he likes. When he has done this he allows you to look at his board for a few seconds; then he covers it over and you have to arrange your men in the same way on your board, within two minutes. You take it in turn to place the men in position, and whoever replaces them correctly the most times wins.