Americas Army
America's army, the official u.s. army game (aa), provides young americans with a virtual web-based environment in which they can explore army career opportunities within an entertaining setting that is tailored to their interests and aptitudes
http://www.americasarmy.com/
Unreal Eninge
Home of the award-winning unreal engine technology, developed by epic games, inc.
http://www.unrealtechnology.com/