Divide class into 4 even teams (e.g. 5 in each team). Each team has a hoop in front of them and there is a hoop in the centre. The hoop in the centre will have 6 balls in it. Each team member must number themselves 1 to 5 (or however many are in each team). When the teacher yells 3 all the 3s run to the centre to get a ball and return it to the hoop in their team. The teacher will blow the whistle at intervals. When the whistle is blown that numbered player must leave the ball wherever it is and return to their team and the teacher will yell out another number to take over the ball robbing. There will be no more balls in the centre hoop at this point so people must rob the other teams hoops of their balls. The first team with 3 balls in their hoop wins. Only one ball can be moved at a time. You cannot stop someone robbing the ball.