Microsoft said this week that Xbox Live will be taken offline for server maintenance on June 16 starting at 12:01 a.m. PD.
"The server maintenance will prepare the service for the various new features Microsoft announced during this year's Electronic Entertainment Expo."
I am assuming this new features they are talking about are integration with Last.fm, Facebook, Twitter, and the TV Broadcaster "Sky", but one can only speculate what they have up their sleeves.