I ran a cap and trade experiment in my class,* to show students how they could benefit from a market that allowed them to trade their (capped permits) for pollution emissions.**
This experiment [65 minute mp3] clarified how "normal" people can listen to the idea but not understand how to implement it.
It also clarified the importance of setting a real cap, understanding whether manufacturers are pursuing profit or volume, and the efficiency with which market prices reveal social values