My students have a hard time staying quiet so I came up with a point system. Each period is worth 20 points. If a student disobeys the quiet rule, the points are subtracted in increments. First they are left with 10 points and then 5 points. After the final infraction, they have 0 points left. At the end of the period, I record a running total of points on a section of the board. They like to see how many they can collect. They can spend them on extra computer time, stickers and treats but I set the prices high enough to ensure that I don't go bankrupt.