Anyways, I have always imagined a to-do list RPG that makes my life more efficient (EpicWin was a good attempt at it, but it was a VERY thinly veiled to-do list), but recently I found someone creating just the app I wanted, and it is called "Habit RPG." It is a to-do list with the form factor and features of an RPG.
As you accomplish tasks, you get rewarded with gold and EXP. Get enough gold to buy items that make it slightly easier to level up (Sword that gives a +5% EXP bonus) OR items to recover HP. Get enough EXP to get access to more stuff. If items linger in your to-do list for too long, your HP and EXP takes a hit.
The system itself is surprisingly robust, and I am very excited for the future of this app. Their Kickstarter is nearly over, and it is fully funded (There will be native Android and iPhone apps on the way). Video games do a great job at addicting us to negative behaviors (Wasting time but feeling like we've accomplished something), and it's about time that those same shots of dopamine be used to make ourselves more productive.
I only post this because I wanted to do something like this for a long time.