Gamification

Gamification is when 'game thinking' and game mechanics are used to make something which isn't a game more fun. In HabitRPG's case, the main inspiration for the game mechanics are role playing games.

Wikipedia's article on gamification has more information on the general concept.

Gamifying Your Lists has an example of further gamifying HabitRPG by the act of renaming your tasks to make them more heroic.