Write a four beat rhythm in each of the nine boxes appropriate to the skill level of the class. Quarter notes, eighth notes and quarter rests work well with primary age classes.
Practice each rhythm by modeling it for the class. Give a few students the opportunity to demonstrate the rhythm for the class before you model it. Quiz students periodically on the last rhythm you practiced.
Divide the class into two (2) teams and then ask them to find a partner. Boys vs. Girls always works well.
Assign the 'X' to one team and the 'O' to the other. Then select the team who will begin the game.
When they are ready, count off 1-2-3-4.
If they clap the rhythm correctly their team will receive an 'X' or 'O' in the square. If they clap the rhythm incorrectly, no 'X' or 'O' will be placed in the square.
Teams alternate whether the rhythm is clapped correctly or not.
Repeat inviting pair after pair to the white board until either team achieves Tic-Tac-Toe-Three-in-a-Row or the game ends in a cat's game.