Recently, however, I came across a new one in the Urban Dictionary, and thought I'd like to share it. So . . . from this former Jew, currently atheist (but who likes the term in the title as well, especially for friends who refuse to believe I'm an atheist), kinda Buddhist, who was raised in a Christian country and is intimately familiar with the holiday now only loosely associated with the birth of Jesus of Nazareth (including that Peace on Earth, Goodwill Toward Men nonsense):
Happy Chrismahannukwanzadan
See this Amp at http://amplify.com/u/jfr0