I've read comments of people saying this can be just a video playing on Zune. Just to remind you videos on Zune play widescreen (you have to flip it to the side). It is possible to create a flipped video anyway :)  

And the background:

The link to this video was posted on ZuneScene forum. The admin of ZuneScene said noelkim who posted this, uses the e-mail address " This email address is being protected from spam bots, you need Javascript enabled to view it ", but this is not an e-mail address Mys Videl uses! Also the username used on YouTube (by the same person or not) is ZuneSceneExclusive. Both accounts are new.

Related Forum threads:
ZuneScene
ZuneBoards

[via EnGadget] 

EDIT: ZuneBoards said this is not a real video from Mys Videl. But the most interesting is they claim for the first time that the "Zune Linux" project really exists:

All Mys Videl does for the Zune Linux is some heavy duty debugging. She does no programming. The programming part is up to her friends, who are also working on the Zune Linux. So please, stop bothering her about it. The Zune Linux will come someday, just please be patient. The ipod wasn't hacked in the first few months that it came out.

Related articles:
Zune-Online is now the home of Zune-Linux
Linux on Zune project is real!