This not-so-cryptic hint seems to be telling us something about Rock Band 3. Hmm, could it be that the game will feature keyboards?

If you download the demo of Green Day Rock Band, released on Xbox 360 and PlayStation 3 today, you'll see this teaser screen, which indicates that vocal harmonies and keyboard gameplay are on the way for Harmonix's next music game.

Of course, this clearly doesn't tell the whole story: Harmonix hasn't said publicly what the controller will look like, how the keyboard part of the game will control, and whether it'll work with its preexisting song library.

Game|Life will, however, be making a beeline for Harmonix's E3 booth so we can report back on all of these things when the time is right.

Image: Xboxlife.dk via NeoGAF