I hate the concept of gamification, it is one of the ugliest words in current game design lingo. The fact that most rewards in gamification are extrinsic make most achievements hollow. In education, people should learn because it is intrinsically rewarding, not because they want good grades.
I played “Zombies, Run”, a gamification-y game, and I enjoyed it.
“Zombies, Run” is a smartphone app that tracks how far and fast you run. The difference from similar apps is that it is set in the oh-so popular zombie apocalypse. As you run, you pick up supplies that you can use to upgrade your base. This kind of gameplay is to me a good example of extrinsic rewards.
In contrast, there is also the game mechanic of zombie chases. From time to time, zombies appear and you have to outrun them. This actually makes the game interesting, as it turns your physical stamina into a resource. You might hold back a bit and slow down when you are not being chased, in order to save your strength. I am not sure if going slowly increases the likelihood of encountering zombies, although it seems zombie chases are tied to specific timed story events. This conservation of energy does however mean that you are not training enough. If you only walk, and then sprint while being chased, later missions become much harder. In this way, choosing whether to take it slow (to conserve energy) or run faster (to increase your stamina) becomes an interesting resource management problem.
Using physical stamina, something that is personal to you and is something you would care about if you downloaded a running app, as a resource actually makes “Zombies, Run” into a very interesting (and dare I say, a teensy bit scary?) game and a good example of gamification done right.