Traditionally, Sweet Husband and I have opened our "official" Christmas pajamas on Christmas Eve. This year, I decided that the Kid needed his when the tree went up. Unlike ours, his pj's are actually very Christmas-y, and I enjoy having a little elf wandering around for all of December.
The pants are (once again) homemade based on the method from The Creative Family. And I had the shirt printed at a local shop. (About a month ago the Kid was running around saying, "I like that [friend], he's a good guy!", so I thought inserting "Santa" would be appropriate.)
All in all, it's a teensy bend of our tradition, but one that I think will happen for many years now--at least until the Kid gets old enough to object to Christmas-y Christmas pajamas.