App: Zero to Hero
I developed a free app for Windows Phone called "Zero to Hero" (thanks to user xMp44x for the name suggestion).
So what it does is letting the user explore his unplayed songs, songs that he did not play yet.
The key point: It's developed entirely using TouchDevelop, Microsoft's on device programming environment. Means it is developed solely right on Windows Phone itself.
App-source (TouchDevelop): https://www.touchdevelop.com/ynjw
Hope you like it.