All it is is a simple graph showing the activities that we do one axis and a scale of 1-10 on the other. 10 is listed as the most boring, while 1 or 0 is then essentially the most exciting.
A lot of students like it when they see it and understand it, and it makes the class kind of fun. I can tell from the graph what activities are good and which are bad. The bookwork invariable gets a high number, while fun activities like cartoon dubbing, or word games such as 5-in-1 get very low numbers, usually close to 0.
The key is then to mix the two, doing just the right amount of bookwork and not a minute more. You have to have your extra activities ready to go and be able to pull them out at any minute.