Probably nothing because Orthodox Christmas falls on 7th of January.
When I first visited Chisinau, Christmas was a scene from the old world.. Kids on pony rides, colorful clothes and posters, and plenty of gypsy beggars.
Most Ukranians work on 25 December, though catholics or others may celebrate 25th. They celebrate Christmas on 7th though from what Ive seen having been here last 2 Januaries is that they do not seem to treat Christmas with the same reverence as in the west, most shops and business seem to be open as normal.
They do have some interesting traditional foods. The boiled wheat thing was pretty bland and made me fart a lot which after a day with the girlfriend I thought I would explode trying to be polite.