Open Source Games http://www.xonotic.org http://www.urbanterror.info/home/ http://en.wikipedia.org/wiki/Id_Tech_3#Projects_based_on_the_GPL_source_release http://www.flightgear.org http://wildfiregames.com/0ad/ (AoE/Travian like game) http://sourceforge.net/projects/warzone2100/ http://glest.org/