Slapcount: Count up and down by a certain number and spell your name while slapping one another's opposite hands.

Blink: Blink with your right eye while you snap with your left. Then switch.

Rock Paper Scissors Math: Using only the numbers 1, 2, 3, and 4, flash any number of fingers between 1 and 4, and the person who calls out what the total sum is first wins.

Say 21: Your goal is to get to say "21" first. Take turns counting up; you can count up by either just one number or by two numbers. For example, you can say "1" or "1,2"; "3" or "3,4".