While not officially confirmed yet, a listing on German offer site mydealz points at the possibility that Ubisoft could be giving Assassin's Creed 2 away for free, to keep, next week.
Free games are welcome at the moment, and Ubisoft has already given Child of Light and Rayman Legends away in recent weeks. Assassin's Creed 2 would be a welcome addition and is considered one of the best games in the series. It also had the brass balls to have a character named Mario proudly proclaim, "It's-a-me, Mario" - how they didn't fall foul of Nintendo's lawyers with that one, we'll never know.
While there's nothing officially confirmed yet, it wouldn't be surprising to see this game given away, and apparently, Assassin's Creed: Brotherhood and Revelations will also be on sale should you wish to continue the story arc.