am i right, or i'm missing something?
You are right. Google Chrome OS is Open Source. But with "Google Chrome OS" you can do exactly nothing, because there are no applications (even basic UNIX tools are not available). The
My understanding is that Chrome OS is based on Chromium OS, which is more FLOSS oriented: http://www.chromium.org/chromium-os
Some months ago I gave a try to this re-build of Chromium OS: http://chromeos.hexxeh.net/
and it was working (it wasn't updated since last February though).
The wiki says that you can install Ubuntu packages, but I did not try: http://chromeos.hexxeh.net/wiki/doku.php?id=addingpackages
So it seems possible to extend it (the question is then whether it would be useful).