They Are Jewish. Get an empty jar and a big bag of jelly beans. Every time someone in the group does something good, ie. This not only motivates single children, but also motivates them to work as a whole group. Jelly bean idea is fine, however, it is never a good idea to take away beans for poor behavior.
Positive reinforcement is much more effective.
Just slow the amount of beans added, but always try to catch them being good. Begin with more frequent rewards. I have a problem with some of the discipline ideas mentioned in previous IdeaNets. Most important is to be proactive and set up situations which avoid poor behavior possibilities. Formal instruction in educational theory, developmental psychology, and behavioral management is important for any Jewish professional dealing with children.