Nixmas is an all American holiday celebrated by Dr. Stephen T. Colbert on which Christmas is based.
It is a holiday where a jolly man who keeps an extensive list of who is naughty and who is nice, who has with a number of little helpers, and is willing to break in to peoples' places in the dead of the night. Obviously that's Richard Nixon.
Nixmas celebrates that President and his hopes and dreams. The Nixmas Tree is the universal symbol of Nixmas.