World War Alpha is a free MDickie game released on July 27, 2007. The game centers around time travel, involving 9 famous armies from all across history. It is similar to Risk, for it involves moving your army into different territories to combat the enemy strategically. The warfare is playable, with many weapons, some new, including guns and lightsabers.
The game is free to download at - http://download.cnet.com/World-War-Alpha/3000-2095_4-10582142.html