This weekend is the first weekend of Onslaught's availability on Xbox platforms -- and to celebrate, Infinity Ward is flipping the switch on Extinction XP, so you can get even bigger gains for your characters while playing the new episode, Nightfall. Keep an eye on IW's Twitter feed to find out when that bonus XP goes live; no time was specified, but it's historically happened before noon PT.
And there's even more happening today. IW is also hosting a livestream from their studios with GameSpot today at 12:30pm PT, which you can watch here. They will be taking your questions, so tune in and chat it up.