My boss is a nonpracticing Jew and we both share a dim view of overcommercialized holidays. If I gave him a gift at this time of year, I think he'd laugh. Because we're both psychology professors, he'd also likely accuse me of being a stereotypically manipulative social psychologist who wanted something from him.
Oddly enough, he has continued a practice that he inherited from his predecessor, which is to hit up everyone in our department for money to give to the secretary. I suspect it's a holdover from the days when faculty relied on secretaries to do all the work they felt was beneath them, such as typing tests and making copies. Since I do all of that myself and set foot in her office maybe twice a year, I don't feel obligated to contribute. Sometimes I wonder if I'm violating some unspoken rule, but so far I haven't felt guilty enough to fork over any cash.
I'm friends with a secretary in a different department whose boss does the same thing, and she finds it very awkward. She works for a large number of older men who dump all their "menial" tasks on her and pretty much treat her like dirt (her boss doesn't, but at the same time he says nothing to the other men about their behavior). I have watched a few of them drop a textbook and stack of notes on her desk and say "I need to you type up this test by tomorrow," then walk off. The last time I pointed out to one that their department has a 48-hour test creation policy, he screamed that it was none of my business and I needed to leave now.
I suspect the money is yet another way of reminding her that "We are lofty and important professors, so here's a token to justify our rotten treatment of you the rest of the year!"
The manipulation, expectations, awkwardness, and strings attached to holiday gifting make me dread this time of year. If I want to give somebody a present, I'll do it regardless of the season. For example, a few years ago, my boss and I were discussing brands of liquor that we hadn't seen in awhile (living in PA means having to buy your booze and wine at state stores, which have a limited selection). Not too long after, I was at a liquor store in New York and spotted one he had mentioned, so I bought it for him.