Lots of companies file for trademarks with the US Patent and Trademark Office, and that includes Microsoft. In the past couple of weeks, two interesting and enigmatic titles have been filed to the USPTO website, and they both relate to games in some way.
One of the filings, made on January 24th, is for something called Marlow Briggs, listed under "game software." The other listing, made on January 15th, was marked by Microsoft as having to do with "Entertainment services, namely, providing online video games."
GameSpot contacted Microsoft when both trademark filings were discovered and both times the company sent back the same response: "Microsoft often acquires various trademarks as part of its ongoing business strategy, but beyond that we have no comment."
We can speculate that "Gunpower" has something related to shooting in mind. Perhaps its an online multiplayer game set in the 19th century. As for Marlow Briggs, that name sounds a lot like a hardcore detective that you might have read about in the 1930's pulps.
In any case, it will be up to Microsoft to reveal exactly what it has in mind in terms of these two rather mysterious titles. Let's hope we don't have to wait too long.