Growing up Jewish my family celebrated Christmas in a very traditional Jewish way, we ate Chinese food and watched movies. The video below helps my fellow Jews improve their Chinese.
But why are Chinese restaurants different from all other restaurants? Most Chinese restaurants are staffed by Chinese people who don't celebrate Christmas. So the opportunity cost of working that day is a lot smaller than a Christian waiter. Even in Columbus Ohio a decent size city where I grew up it was hard to find much ethnic food other than Chinese until the mid 90s, this trend was similar throughout the country. Now I would guess there are more Thai and Indian places open for Christmas. However, if people associate Christmas with Chinese food, then other ethnic restaurants might not bother opening. Local DC food critics though suggest looking into non-Chinese options, since DC seems to do both Thai and Indian better than Chinese food.
Now why are the movies open? Movies are a capital intensive business. A movie theater only needs a couple of people to run it. Also movies are a great way to spend time together without talking to each other, a much needed gift during the holidays.
So enjoy your Christmas!