In demo-ing the kinect and programming some different looks, I came up with this particle system / liquid simulation.
What I'm really liking about it is that I have a particle for every single pixel, and the physics reaction is happening swiftly in 3D space, being calculated off of a live video feed (the depth channel) and re-textured with another video feed. That's not chopped liver.
It's really interesting to see the areas dissolve into fine pixel dust. Also, this works fully with OpenGL Lighting and QC's shadow effect.
This is also cool to me, because the technique isn't bound to the kinect. It's the basis of what is seeming to be a really efficient technique for particle systems on the GPU with OpenCL. I'm looking forward to refining it further.