Does your school use it? All the schools in our district do. It's a bit different at each school. It works very well. The idea is immediate recognition of good or bad behavior.
The children start on Green and if they do something good, they go up to Purple. If they do something bad, they go to Yellow or Red. They can recover. They really want to go to Purple! If they are Green or Purple at the end of every day for the quarter, they get to pick a special activity.
They also get coupons for doing the right thing. They can spend the coupons once a week on erasers or stickers, etc. Class behavior during a Special gets them up to 4 marbles. The first class to fill its jar gets a pizza party. Good class behavior in the cafeteria (always a challenge) also gets them pizza.
One of the things I really like is that perfect attendance and no tardies for the week means they participate in the Friday morning dance party, which adds a physical fitness aspect. The kids really enjoy this. It is cute to see the 1st graders trying to do the Macarena.