HTML emails with christmas boxes that say don’t open till X-mas.
Special forum with the same title. IF somebody goes into the new thread then have a big picture with Ryan saying "HEY! NO PEAKING!"
Filler topics could include:
Have you been a good boy or girl this year?
Have you eaten your veggies?
Are you sure you aren’t going to get any coal this year?
Now of course, we do have to put aside the "feely touchy" issues of religios conotations if we do something like this but ... ahh heck it’s still just X-mas

and most folks will probably just write us off as Americans