HabitRPG takes the tasks you want to complete and turns them into a role-playing game. The game allows you to earn experience points, gain levels and stay alive by getting things done.
HabitRPG takes habits that you want to build and gives you experience points for completing them. If you fail at a habit, you lose health points. You can also add single to-do items that you simply check off a list to gain experience. If you lose all your health, you lose the game of HabitRPG. If you gain enough experience, you'll get to the next level and your health will be restored. You also earn gold points for completing tasks and making positive progress on your habits, which you can use to (figuratively) purchase items like weapons and potions from the store to help you on your journey.
Unlike previously mentioned iPhone app Epic Win, HabitRPG is free to use/play and available to all platforms via the web. HabitRPG also wants to become a mobile app, but needs funding to get there. You can help by backing the project on Kickstarter if you're interested.