One of Activision's last RTS games, Dark Reign 2, has gone open source under the LGPL. Although the release by a former Pandemic Studios employee was some time ago, it had happened relatively silently. With the source code now available, it is hoped that online play that isn't dependent on WON servers will be implemented and possibly ports to other platforms.
http://games.slashdot.org/story/12/0...es-open-source
