The Leap Motion Controller captures the movement of your hands and fingers so you can interact with your computer in a whole new way. Swipe, pinch or grab in the air and magically see your actions on your screen.

The Leap Motion Controller is just 3 inches long and takes up hardly any room on your desk, but has a wide 150° field of view, and transforms the space above into a 3D interface for your hands. It works alongside your keyboard, mouse, stylus, or trackpad for a richer and more natural 3D computing experience. It uses infrared cameras and highly complex mathematical algorithms to translate hand and finger movements into 3D input.

Interact with virtual objects like you do in the real world by using it with a 3D headset like the Oculus Rift. 

Buy here for $90.

Manual can be found here.