Do you mean Festivus? I don't know any Mormons who celebrate that particular non-holiday.
I don't know any who celebrate Joseph Smith's birthday either. (In fact, until you mentioned it, I had forgotten that today is Joseph Smith's birthday.)
But most of us do celebrate Christmas. So, allow me to wish you a merry Christmas and a prosperous new year.
By attending a Christmas Eve service at church on Friday, December 24 or a Christmas Day service at church on Saturday, December 25?
(Seems like caucus rules aren't being enforced, so I dare to post a request for clarification.)