It's the season for giving away free games. Following on from Blizzard's decision to drop the price of StarCraft 2 to zero, Ubisoft is giving away two excellent titles from its back catalog: Assassin's Creed 4: Black Flag and World in Conflict.

Ubisoft explains that the promotion is part of an anniversary celebration. It's been ten years since both the real-time strategy and the very first Assassin's Creed game were launched. If, like me, you can remember these releases, finding out it's been a whole decade since they arrived will likely make you feel even older.

Before the arrival of Origins, most people's favorite Assassin's Creed title was either Black Flag or the second game in the series. The adventures of Edward Kenway and the fantastic naval battles make it my pick of the franchise. Just over four years since it launched, Black Flag still looks great and is a joy to play.

World in Conflict is one of those games that, despite overwhelmingly positive reviews, is often missed when it comes to naming the all-time best RTS titles. Set in an alternate 1989 and taking place a few months after the start of World War III, it features one of the best tactical nuclear strike weapons in gaming history. Ubisoft's giveaway also includes its Soviet Assault expansion.

To take advantage of this offer, simply log into Uplay, where you can download and permanently keep World In Conflict until the deal ends on December 11. Black Flag, meanwhile, is free from December 12 to December 18.