From - http://xbox.joystiq.com/By: David Hinkle
Double XP weekends are usually only reserved for Halo 3, Call of Duty 4 and Call of Duty: World at War, but now that's about to change. For every enemy you chainsaw or shred with your precious shotgun (or just kill, frankly) in Gears of War 2 this weekend, you'll receive double the experience points. It all starts on Friday, May 15, at 5 AM EST, when Epic will throw the switch and let the rushing river of XP flow. You'll have until Monday, May 18, at 9 AM EST to take advantage, and the double XP will count across all playlists and match types. So, break out the WD-40, grease that chainsaw up, and get ready to show the Locust what's what.
[Thanks to everyone who sent this in!]