I work as a sub, and have done everything from SpecEd to gifted, and from K-high school. One day in a PE class I talked to the kis about how athletes cool down after exrcise. I told them about how we "speed up" while exercising and that we go back to "normal" afterwards. Then I showed them how to feel their pulse, and see the difference in heartbeats while still all keyed up and after a cool down. That day, as I was leaving the school, I saw one of the kids from my PE class showing anothe student how to feel their pulse! It was so cool. Not only did my student learn something, but she became a "teacher" herself, as she showed another student what SHE had learned. It made my day!