This comment doesn't really go anywhere, just some vague thoughts on fun. I've been reading A Theory of Fun For Game Design. It's not very good, but it has some interesting bits (have you noticed that when you jump in different videogames, you stay in there air for the same length of time? Apparently game developers all converged on an air time that feels natural, by trial and error). At one point the author asserts that having to think things through consciously is boring, but learning and using unconscious skills is fun. So a novice chess player gets bored quickly having to think through all the moves, while an expert 'just sees' the right moves, and has fun. It made me think of the concept of flow and of Alan Kay's work on Squeak and Etoys, making learning more fun and intuitive with computers (particularly learning mathematics) I think it's called constructionist learning.

It does seem though that we don't have much of a theory of fun, most of the stuff we know we learn through trial and error. If we had a decent model of fun we might be able to make boring learning activities fun, which would help with motivation and akrasia and so on.