Thank you

If the context was 2 or more people talking about skiing or going to see Christmas markets, it is a reasonable question to ask anyone who hasn't already contributed. (For people North of the equator!) It would also be a reasonable question to ask someone who had stated that they have winter holidays. I remember hearing somebody state that he could spend time in the sun, because he was a butcher and spent a lot of time in a cold room.

I would say "What have you done in your (last) winter holidays?" :)