This is for the WHOLE CLASS! Just buy a regular old cookie sheet and attach magnet tape to the back, and then stick it to your white board. Anytime the class as a whole are doing a great job by listening, following directions, being responsible, finishing their work, working quietly, etc.... you can give them a "brownie". When they fill up the whole tray they can pick from the mystery envelope (which is taped to the bottom of the tray for a great mystery). The students can earn extra recess, lunch with the teacher, popcorn party, or an afternoon movie.