To start with, it's obviously not a day off here. We usually celebrate on Saturday, since employers typically don't go for "But it's a holiday in my/my spouse's country!" in our experience.
This year we celebrated with a young American family who recently moved (back) to Czech Republic and our friend A, who is originally from South America. It was a totally mixed afternoon of English and Czech, which was kind of fun. Most of the time we hang out with people who are one language or the other, so it's fun to spend time with a group that does both. Lets the Slovak and I speak our true native language: Anglo-Czecho-Slovak.
We had turkey pieces, stuffing, mashed potatoes, brussel sprouts and green bean casserole. I had to make the stuffing and green bean casserole from scratch, of course, because you can't get the typical mixes and pre-made ingredients (cream of mushroom soup, French dried onions, etc.) people usually use in America. They turned out pretty yummy, though I say it myself.
My favorite moment of cultural syncretism was using rohlíky to make my home-made bread stuffing. It sounds funny, but it works!
K enjoyed playing with our friends' baby. She once referred to him as her "brother" and also has started talking about her baby dolls as her "brother" and "sister". I think she's trying to tell me something, don't you?