The Secret World doesn't do Christmas events. Instead the entire in-game event this holiday is based around the impending apocalypse.
As well as the currently running ARG (I'm still working through it and compiling my thoughts, but it is epic! There have been tens of thousands of people helping out with it so far) Funcom have now released details on the actual in-game event.
The dead will be rising in places normally safe from such things, and three huge Harbingers will be spawning as dynamic events around the game world. There will also be missions leading up to the battle with the Mayan God of Nine Destructions (at two difficulty levels), as well as the opportunity to earn gifts in the form of pets, weapon skins and clothing.
You can read the full blog from senior designer Tanya Short here: http://www.thesecretworld.com/news/blog_the_end_of_days
Finally, with the release of the event as part of Issue #5, Funcom have released the cover image for the Issue, along with a short comic, which you can see below.
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