Recently launched, Promise or Pay is a social enterprise that makes you vow to do that one thing (or many things) that you wish you did more. Can you just not seem to motivate yourself to go to the gym a few times a week? Or stop eating sugar? Or write poems?
There are a wide range of online apps aimed at productivity and motivation, especially in the "life hack" variety. But here, there's a social component to the web-based app in that once you put out your promise to the world, you're held to your word or you must pay the amount of money nominated to a charity. It's what's called a win-win.
Promise or Pay website
Promise or Pay on Facebook
Promise or Pay on Twitter
Promise or Pay on YouTube