are you sure?
• Purchase any “Gears of War” content from Xbox LIVE Marketplace (including a “Gears of War” Game Add-on, a “Gears of War” Games on Demand title, or a “Gears of War” Avatar item)
• Play 20 or more hours of the “Gears of War 3” beta (any time already spent in the beta will count toward this challenge)
• Add a 12-month Xbox LIVE Gold subscription to your existing account (purchased from retail or online)
• Play more than 100 hours of any “Gears of War” title, lifetime to date