I was teaching on how a small amount of sin can effect our whole life. I prepared some mud prior to the event in a large container. I divided them into groups of 2 or 3 and had them make mud pies in pie pans. Some got into mud fights which made it even better. I then had a contest as to whose was the best. At the end I then told them that the mud they had been playing with had one extra small ingredient, dog poop. (Not really though) After they were all pretty disgusted, we then talked about how even a small amount can ruin the whole thing just like sin in our lives.