I have added some videos with similar technology to that seen in Project Natal, the companies who developed the technology showed in the videos are said to have been purchased by Microsoft for the development of PN - so what you see in these videos could be a few examples of the sort of things you will have to look forward to with PN, only less advanced!

This is one of the videos, you can see the rest on my Project Natal related videos page (in menu, above).