Leap Motion is a tiny device that allows you to use your hand to interact with your computer other than using keyboard, mouse or trackpad. Just simply wave your hands above the Leap Motion controller and it can detect your hands movement. Think of it as Kinect for computers but smaller and works on both Windows and Mac.
It can tracks all 10 fingers up to 1/100th of a millimeter, your movements at a rate of over 200 frames per second and have wide field of view (150°) and a Z-axis for depth.