Christmas event?
Won't be until December, I don't think. I assume we'll have another Thanksgiving mini-event between Halloween and Christmas...
Forum Discussion
The Xmas update will probably come sometime the second week of December, I'm thinking the 9th or 10th. This should give you plenty of time for a redesign unless Halloween gets extended past November 12. The one thing to keep in mind is greenery may look odd when the trees comes back in spring, so plan for some time to touch up.
