Ryzom is a Massive Multiplayer Online Role-Playing Game (MMORPG) developed by the French company Nevrax. It is based on the NeL game engine (also from Nevrax), which is GPL'd already.
As "due to market conditions and other unforseen cirucumstances, a request to begin bankruptcy proceedings has been filed at the commerce tribunal", the Free Ryzom Campaign has formed with the aim to buy the source code and game data and release it under the GPL:
Help us make Ryzom a Free MMORPG! Donate now to help us purchase the source code, artwork and other game data associated with Ryzom, so we can breathe new life into it as an open, democratically run player project.
They've even set up a Social Contract (modeled after the Debian Social Contract) which states among other things that "Ryzom and all materials produced by the Free Ryzom Project will become and remain 100% Free Software".
If you want to support the project, you can make a donation pledge (used to convince the official presiding over the liquidation process). No real donations are possible at the moment.
More info/material on the game:
I'm looking forward to the day where I can
apt-get install ryzom and play a fully free MMORG...
 I recommend using the Mozilla/Firefox/Iceweasel VideoDownloader extension to download the videos and watch them with mplayer.