So says the Major. Next Tuesday (March 27), between midnight and 2:00pm Pacific Time (in the US), Xbox Live will be down for maintenance. So will Xbox.com and the Xbox forums, but...meh. Fourteen hours is a long time. Better start stocking up on provisions. Or you could dust off that singleplayer campaign you've been neglecting for months. Or...you could go outside.
Oh, and before you get your hopes up, no, this isn't a dashboard update, so untwist those knickers. Stat.