I live with my three sons ages 6, 11, and 15. Every Christmas Eve we sit around the tree with 3 large boxes underneath it. 2 contain gift cards to department stores, and one contains a large shaving cream pie. Whichever boy randomly picks the box containing the pie gets to smash it in my face, but, then gets one in his face from me. The boys may trade gifts if they want, but once the pie hits my face, trading is over. Then, after cleaning up, we all watch the fireplace and sleep together on the sofa.
The next day, we get presents. We always get new robes and slippers, and I always get a new briar pipe. These traditions were passed down to me by my father, who did this with me. The only difference is that I was the only child, so I always got pied. Tradition also states that on one's 18th Christmas, he receives his first pipe.