As there has been quite some fuzz about Kinect / Natal the last few days, I'll throw an egg in the basket as well.
At NUITEQ, we have some very bright software engineers, that are in addition to multi-touch also specialized in image processing, so in the Summer of 2010, we applied for a small EU funded R&D project, to work on a 3d camera depth sensing technology, similar to Kinect / Natal.
Our application got approved and we had some great fun during the project and learned a lot of exciting new things.
You can find the project report here in Swedish.
And thank you Google, for your translation here in English.
A quick and dirty demo video of the result, you can download here.
The hardware that was used came from a company called Canesta, which last month got bought by Microsoft, as obviously Natural User Interface and new ways of interacting with technology is an important element on the Microsoft future product roadmap.
If you have the money, make sure to get a Kinect yourself as well, its an awesome technology and great fun.