At the beginning of the Cub Scout meeting a candle is lit, and as long as there are no disruptions, the candle stays burning. As soon as someone disrupts the meeting, he must blow out the candle. Once the candle burns all the way down, the group gets a special treat.
Naturally, it's in everyone's best interest to keep the candle lit, so the children help keep each other in line. You can adapt this technique to get jobs or homework completed or to improve table manners among siblings. Don't use this technique, however, if one child is going to be too frequently singled out.
From "The A.D.D. Book," by William Sears, M.D., and Lynda Thompson, Ph.D.