One thing we do with our kids is to line them all up at one side of the dojang, then when we say go they have to to 1 technique for every step they take and go all the way to the other side of the dojang. If they take a step and dont do a technique they have to start over. We do that a couple times, then we put down a challenge for them to do it again, but this time they can only do a technique once. I think it helps to make them think and realize how many techniques they actually know, as well as to get out some extra energy.