The other day Michael Gannotti made a post about a very interesting SDK that popped up that helps enable developers create ‘touchless’ applications using webcameras.
Check out this short video clip here: http://communityclips.officelabs.com/Video.aspx?videoId=a89a217b-fc38-4a6c-87f8-ab59a2028391
Or endeavour it out by downloading the demo here: http://www.codeplex.com/touchless/Release/ProjectReleases.aspx
I remember a plethora of applications like this that used to exist, but it was really hard to find a good SDK to help you get started or give you an area in the community to share ideas, as well as now it looks like things are moving in a good way. Especially as the cost of touch screen technology as well as multi touch technology is still far more expensive than a simple camera  
It’s very cool stuff as well as I highly recommend checking it out: http://www.codeplex.com/touchless
Looking forward to the future,

Richard Harbridge