Do you mean your child goes to another university and they want to take a class at a community college during break? If so, it depends on their university rules. My kid can only take certain non-major courses at CC and they need to be pre-approved first. They also cannot overlap with his fall or spring semester (not even by one day).

^that link notes last year’s offered classes though. Fairly limited, it seems.

Last year’s Winter Session ran from Dec 18-Jan 18. Probably will be in that range this year. They consider it an extension of their Spring Session that starts in late January (I think it was something like the 23rd this year).

As for actual class offerings, those would likely be published in the fall.

https://www.nvcc.edu/admissions/apply/winter-session.html

Has anyone done this at NOVA or somewhere else?

NOVA has been surprisingly non-responsive on the issue of dates and what's offered (and maybe they don't know yet but just say that). Do you know when, typically, that session is and what is generally offered?