This Codeplex project is SO cool.  Imagine being able to use your webcam to direct your computer.  Just make gestures in the air with known object. Kind of like Surface for the rest of us, I guess?

Here's a video of it in use:  http://www.youtube.com/watch?v=hJuJJOK7MMc&fmt=18

 If you are ready to start, get it here:  www.codeplex.com/touchless