This weekend, all willing Abstergo agents will have a chance to strap into their animi for the first (of hopefully many more) http://www.trueachievements.com/AC-Revelations-xbox-360.htm
double XP weekend. Ubisoft announced via the Assassin's Creed Facebook
page that the event will begin today, December 16th, at noon EST.Update:
The double XP weekend will end at 3 am EST, Monday morning.
If you're looking for some new characters with which to assassinate your targets, you may have interest in the new "Ancestors Character Pack
", which adds four new multiplayer characters and an achievement for each of them too.