This app motivates you during your runs by letting you set PowerSongs to boost you through to the finish line. You can also use the app to post a status on your Facebook wall and hear mid-run cheers in your earphones every time one of your friends likes or comments on it. Do you have a competitive spirit? The app’s built-in game of tag should slake your thirst. The feature lets you battle it out with other runners to see who holds the title of fastest.