A 2007 AEP post, UI control via webcam, mentioned XTreme Reality 3D, "a piece of software that works with your webcam to let you control applications and games with your hand in real space." It turns out that others were working on similar controls for TVs, according to NewTeeVee in Hands On with Softkinetic’s Hands-Controlled TV. Here's an excerpt:

"We write a lot about how the world of content available through your television set is undergoing a dramatic change. But the changes happening to your TV aren’t just what’s on or how it gets there, but also the way you interact with your TV set. Forget remote controls and buttons when you’ve got hands to change the channel and adjust the volume. We’ve been following this gesture-controlled TV trend for a while and recently sat down with Softkinetic to get a demo of their solution."

Here's a few demonstrations of the trend: