The Metal Gear Rising: Revengeance demo slices up Xbox Live and PlayStation Network on January 22. Konami also released a new seven-minute 'Jack the Ripper' trailer for the game, as edited by a certain Hideo Kojima.
This is the same demo as included with Zone of the Enders HD Collection, released last year in October. With a week left to wait, buying that now just for the demo is inadvisable.
Metal Gear Rising: Revengeance is the new name for Metal Gear Solid: Rising. The project is now a collaboration between Kojima Productions and Platinum Studios for Xbox 360 and PlayStation 3. The project was originally announced at the Microsoft E3 2009 press conference.