http://www.mindch.com/2011/02/official-microsoft-big-hardcore-games.html
ast week, Geoff Keighley wrote on Twitter that Microsoft will be hosting an event before GDC for undisclosed title; the news fell completely off the radar until now. Aaron Greenberg has confirmed the existence of the event, as well as it's content and the official date.
There you have it, you can expect to get new details about Microsoft's offerings for the core gamers this week. With E3 being relatively close, don't expect them to show all their games, they know they have to wait for the biggest event, but let's hope it can hold you off until June.
Small Update: The press conference hasn't been confirmed in a press release yet, so there's a chance that it might be an NDA event (Non Disclosure Agreement). This means that we might not be able to get any announcements until GDC. As soon as anything comes up, we'll keep you updated .
