This is a great way to get way to get the whole class on task. They work together to "Beat the Teacher" which helps them monitor their own behaviour. Decide upon a reward as a class before you start playing - a sports game at the end of the day, free time, show & share... Whatever works! Students love coming up with the reward and it entices them to work even harder. Laminate this and use white board markers to re-use over and over again.