I used to send Christmass cards to all of my friends, regardless of their faith. As an atheist myself, I thought it was amusing. But any religious overtones the holiday may once had have been obscured by rampant consumerism and a mythological race of enslaved midgets.
In other words, the irony was lost.
One year, while researching the various pagan origins of Christmass, I came across the ancient Roman celebration Saturnalia. It was exactly what I was looking for in a holiday and I've set about the task of reviving it.
In other news, I had no idea sphinxes were real. But they are. And they are fucking ugly, hairless, man-cats.