Speaking of tradition—my oldest son, Daniel, has one that he and his friends have observed every Christmas for years. He and his friends pile into Ryan's basement for a 24 hour period to play computer games. Ryan's sister, they declared, was a nuisance, so blocking her from the basement became part of the tradition.

Mind you, all of these young men are in their twenties, and Ryan's sister moved out of the house a long time ago. But it wouldn't be a tradition if it didn't persist.

As years went by the plans for blocking her, but not her mother (who had the cookies, after all), became more and more elaborate. This year, in addition to the required draperies of blankets, and secret knocks, Daniel designed a drawbridge. This involved an old screen door, pulleys, and counterweights of two-liter pop bottles filled with water. The 'secret' way to open the drawbridge was to tap gently on a particular spot, helpfully labelled 'tap here'. How this deters the sister, I don't know, as she's been able to read for over fifteen years.

Daniel, being Daniel, developed official blueprints for the design before he came from college. He demonstrated it to his father and me in academic-Daniel fashion. He'd discovered a design flaw which irritated him considerably.

"Well, you see, I guessed that coefficient of friction between metal and string was 0.2." He shook his head in disgust. "It's probably closer to .25."

I had no idea what he was talking about, but I'm a mother, I tried. Comfortingly, I told him that I would've made the same mistake. After all, wouldn't you?