The Third installment to the Assassin's Creed Franchise.
Note: "Assassin's Creed: Brotherhood" is regarded as game number 2.5, since it picks up right after AC 2 left off and does not include ground breaking updates from the 2nd installment, instead of 3 (AC Revelations) according to its fan base.
Dude, did you hear about the new Assassin's Creed Revelations game coming out? Its going to be the best yet!!!