So.. any ideas how do they do that? My opinion it is simple hand tracking by skin color.

Yeah i saw this on engadget some of the comments where ridiculous! It is a sheet of eyeliner film which works like a 50:50 mirror check out this link to there page http://www.eyeliner3d.com/musion_eyeliner_mechanics.html it shows you how the system works. Very simple but very impresive. 

Now to the speculation i personally think he has two infrared pens one in each hand and the camera tracking the infrared might well be a wiimote as it is the simplist way to track infrared blobs and get the info to do stuff

Check out Johnny Lees Page and download the Wiimote white board app it works really smoothly.

he seems to move very unnaturally if you assume that the color of the hands is tracked, it seems like he holds something in his hand, my bet is also some kind of ir source like pen or remote

I agree with Harry , it’s to precise to be hand-color tracking. It’s possible that the tracking is done with another camera and is filmed with this one , so we can’t see any IR light from he’s hands.
Impressive non the less.

It definitely looks like he is holding something.  I have done LLP tests is mid air, and they do work.  You have to be perfectly lined up though.

LLP in mid air? Can you film it or something? That’d be interesting.

that’s remind me my touchless wall :
http://nuigroup.com/forums/viewthread/2414/
between 1’28 and 1’33 ,it seems clear that is holding something in his hand

we should ask agent John Anderton from Nexus to zoom in (MIn.Report)…