Harmonix will be hosting a panel discussion at PAX East 2012 called, "Harmonix and the Evolution of Beatmatch Gameplay", and the description of the panel seems to indicate that the Rock Band developer will be introducing a new game at the convention.
According to the description, "The panel will include gameplay examples from internal prototypes, honest discussion of our design process successes and failures, insight into how we create and test our games in development, and a synopsis of the design history of a title on public display for the very first time at the Harmonix booth."
The new game is likely to be the new game that is allegedly going to launch on Facebook, Xbox Live Arcade and PlayStation Network.
PAX East 2012 will be running next week from the 6th through the 8th April. Stay tuned.