Android: Galaxy S4 owners enjoy a variety of air gestures that control aspects of their phone without actually touching the screen. Hovering Gestures brings some of that same functionality to other devices.
The app uses your phone's proximity sensor to detect any hand waves above the screen. You can configure the app to use these gestures to open specific apps, silence alarms, control audio playback, or return to your home screen, among other functions. You might not want to use the app all the time, but it's great if you're wearing gloves and can't properly use your screen.