Developer SoftKinetic specializes in gesture recognition technology, and has put that technology to use in the headliniest of ways: Angry Birds. Using the iisu middleware, which allows 3D gesture recognition to be added to any application (if a special camera is present, of course), Softkinetic put together a tech demo of Angry Birds with gesture controls.
It's incredibly intuitive -- if possible, it's even more intuitive than the touchscreen controls in the mobile versions. Basically, you just grab the bird between two fingers, pull back, and let go to throw.
Now, we wonder what kind of gestures other mobile devs can think of for Angry Birds.