Here is one idea that has worked for me. I was having a bit of trouble with the children behaving in children's church, so I made a reward system. I took some colored paper stock and I printed out fake one dollar bills and I made a reward system where they could earn money by having good behavior, answering review questions and being a good helper. They could also lose money if they didn't behave. Then at the end of the month the kids get to purchase items from the Prize Chest. Then the next month they get to earn the money again.