The invites have been sent (albeit without a venue named) but somewhere in Los Angeles, Microsoft are about announce something.
The word on the street is that they are going to announce an own brand tablet, or a new ebook reader, or something that combines the two.
The recent deal with Barnes and Nobel reported to be in the region of $300m is driving this speculation, as it is thought the new tablet/reader could have access to Barnes and Nobel’s ebook store.