This alternate reality game was initiated by mysterious packages delivered to select members of the gaming and blogging community – anyone from individual forum members to Wired. In the packages were large, heavy, cogs - each labeled with a unique code to enter at the Gears “Last Day” site at: http://www.gearsofwar.com/lastday Codes – or CSID#’s - engraved on cogs provide glimpses into the story, characters, and dramatic events from the GOW universe - in the form of videos, images, and audio clips. The online experience, a war torn landscape from the Gears universe, slowly reveals events that transpired in the six months between the end of Gears of War and the start of Gears of War 2.

The inherent nature of gamers spun off into spontaneously created blogs and communities, digging deeper and deeper into the mysteries of Gears of War 2 and finding that the tags were hidden all over the world. 1,000 cogs had been found in strategically placed spots such as a desert in Reno, NV, a fountain in Philadelphia, a stone wall in Toronto, and as far away as Budapest.

Microsoft has announced that debut weekend sales of the Xbox 360 game "Gear of War 2" topped 2 million units worldwide.