MegaGlest is an open source 3D-real-time strategy game, where you control the armies of one of seven different factions: Tech, Magic, Egyptians, Indians, Norsemen, Persian or Romans. The game is setup in one of 14 naturally looking settings, which are crafted with great appreciation for detail. Additional game data can be downloaded from within the game at no cost.
Not perfect. Health doesn't show over units and the "timeout" for the downloads is just annoying. Also, the voice acting is quite bad. Other than that, it is a great game and the graphics are decent.