Recently, someone wrote me about my book, claiming they had finished all of the challenges. I'm not sure if the person was serious (there are over 300 of them, after all), but it got me thinking about books and games, and the difference at the end of each.
It struck me that when most students finish a class, there is a sense of relief. "Finally, it's over. Now I can sell my textbook, throw away my notes, and forget all the stuff I just spend three months cramming into my brain." We approach games very differently. Maybe you just beat God of War 2 or Bioshock or Fallout 3 or whatever, and there is a sense of closure there... but there are also a bunch of locked Achievements, secret levels, more intense difficulty modes, different character classes or progressions, all kinds of other things that give the player incentive to keep going after it is "over".
What would classes be like if they had this kind of incentive system? Where students voluntarily chose to go back and read the chapters that weren't covered during the main course (the way they would explore optional levels after completing the main storyline of a game), do all of the end-of-chapter exercises that weren't assigned (like optional sidequests), write their own material summary to help other students (like writing a FAQ or Walkthrough of a game), or discuss the class and some of their ideas about the material with their friends?
"I just beat the final boss in Vector Calculus yesterday. But I was thinking of going back and collecting all the secret bonuses in each chapter, building up my Trig skill, and maybe going through the book again on Hard Mode and unlocking the bonus chapters on Differential Equations at the end. And I'm totally pre-ordering the sequel class, I hear they're releasing it in the Fall." It sounds ridiculous, but really, why not?