As previously hinted at, here is the teaser site for Sega's "Project Omega". Under September 13, the Japanese character "de" (デ) is written. It seems like each day a new phonetic katakana title will appear, revealing the game's name.
There's also a lady in a black dress with an icon on her chest. Not sure what she's going to do everyday... Oh wait, I am because Sega accidentally left some of the images on the teaser page.
The actual countdown ends on September 20.
Project Omega [Sega]