Microsoft is investing huge in gaming industry with corporation of starter game development companies like Sledgehammer games
they have recently sponsored a event call "Call of Duty XP" which was held on early September.
In that event their main intention was to promote xbox 360 console and the xbox version of the game Call of Duty Modern Warfare 3.
This is somewhat a new advertising strategy.
see here for details
http://www.callofduty.com/xp