The "Casino Night Pinball" DLC will include a pinball mini game, set in the Casino Night stage, to enjoy alongside the main game. The DLC will cost USD $1.59, GBP £0.99, EUR €1.59, AUD $2.99.
Sonic Generations was released on the PC, Xbox 360 and PlayStation 3 on the 4th November. The blog did not make any mention of a console version of the DLC, though it's possible that it could be undergoing certification.