Do you know the website The Pop-Up City? They always share cool things (subsribe to their newsletter The Pop-Up City Daily, really!).
Today, their newsletter covers Strut: an app that gamifies travelling. Using the app while being on the move, you will turn tiles on a blurred map. The effect: more and more of the world will be visible, simply by you going places. After a while the app will show you what your radius of action is (how big, or maybe how small: take another route to get places!). Sweet! (iPhone only, no Android version yet)