Did you lose out when you were disconnected from Ubisoft’s DRM servers? Ubisoft has come up with an apology for those affected by the downtime with an offer of free stuff.
According to Kotaku, it seems that PC players of Assassin’s Creed II who were affected will either get the extra map content for AC2 (like the Arsenal Shipyard) or their choice of one of four games: Tom Clancy’s H.A.W.X, Heroes Over Europe, Endwar, or Prince of Persia.
It’s not quite clear on who got what offer, but as the article points out, it might depend on whether you have the Special Edition or the normal release.
Personally, I’d go with Prince of Persia.