From the moment Kinect landed in the homes of people, it was inevitable that this would happen. The only thing in question was when. The answer is now. There is now a video on the internet of someone using Kinect to recreate a lightsaber.
The creator basically did what every kid has done before and used a wooden stick to pretend he was Luke Skywalker. Except he also used the OpenKinect drivers and OpenCV to overlay light effects in real-time, so I guess his imagination just isn't as good as mine.
This is really starting to bug me. We had better see some revolutionary stuff coming out of the developers making games for Kinect. The last thing I want to see is the general public putting the industry to shame with their creativity and that's already seeming a likely proposition.
Real time lightsaber on the Kinect on PC [YouTube -- Thanks, Jake!]