Those of you waiting for the first hit of Civ 5 DLC khan get it right now for free. The Civilization and Scenario Pack: Mongols features Genghis Khan and his armies, and is a free gift to players. Also, the Babylonian Civilization (the Civ version of it, not the real thing) is available for $4.99.
Developed by Firaxis Games, Civilization V reinvigorates the classic turn-based strategy genre with an astonishing new engine built from the ground-up for this flagship edition of the Civilization franchise. Players are introduced to an entirely new combat system, deeper diplomatic interactions and a cavalcade of expanded features that deliver a fully immersive experience. Players build and defend their empire on their quest to become the greatest ruler the world has ever known.