Got this from the ubisoft forums:

Templars. Assasssins.

Kill the traitors in our Wolfpack mode, and get a double XP boost when you reach community goal, starting January 18th!

"The fierce fight of patriots for independence has disturbed some soldiers' principles and shaken their loyalty.
Mutinies have started in several strongholds and officiers fear their own men.

Rewards: Community reward is a double XP boost and a 40% discount on all Warrior packs from Monday, January 21st (3:00 AM PST, 11:00 AM GMT) or from the moment the community reaches the goal if they reach it later, to Wednesday, January 23rd (3:00 AM PST, 11:00 AM GMT).
Individual reward is a new relic to wear proudly during all your games.
Participation reward is a special title to thank you for taking part in the effort.


Now for a brief explanation on how events will work in Assassin’s Creed 3.

1. The important thing to know is that there are only access two ways to access the event. Either by selecting “Events” in the main menu, or by creating a "Custom Match" and selecting the Event as "Game Category". Whatever you will be doing in the other modes won’t be taken into account towards progression for event objectives.

2. There are three challenges to achieve for each event. Obviously, they vary from one event to the other. Each of these challenges will give you a very special reward… if you manage to accomplish their objectives.

Participation Challenge: the only condition for this is to participate in the event at any point before it ends. (Yes, you will be rewarded for this.)
Individual Challenge: this challenge requires *you* to accomplish a certain objective. And obviously, the reward for that one is more interesting than the reward for the Participation Challenge.
Community Challenge: this challenge requires a massive effort on behalf of the community to unlock the reward – and that one is a very special one. Once community reaches the goal, the community reward is unlocked for everybody.

Note that it is possible that some events last a bit longer after community has reached their objective to allow for players who didn't get to play during the event to get the participation and individual rewards.

3. During events, you will see that very special costumes are available for purchase: the Warrior costumes. Each character has one, and they can only be purchased while the event lasts. Once the event is over, you do keep all costumes you've bought though. You can preview the costumes under "Customization" but we also included sneak peeks below.


The costumes are just the warrior costumes that were available during the last event. Community reward is pretty sweet-Double XP!, especially if the community can unlock it early. It would be nice if we can invite are friends into a Wolfpack mode. Trying to get confirmation of this. Would make sync kills much much much much easier.