This is most certainly an appropriate topic for the forum, Steve.
I know that the Slavs have a lot of unique customs. For Greeks, Christmas is not really a big traditional holiday, and much of what is done now is reflective of contemporary Western/American customs.
There is, of course, the tradition of the Philip's Fast. And a tradition of giving gifts. But there are no Greek carols (we have one, written about 50 years ago), no mangers, no Christmas trees (well, it's changed a bit in the last decades with French/English influence), but it's not really a big thing.
There are customs for Epiphany with the blessing of the waters and the tossing of the cross that the young men dive into the water to retrieve. But actually, St. Basil's Day (Jan 1) sorta kinda overshadows Christmas. St. Basil's Day has a special bread (Vasilopita) in which is baked a gold coin. The one who gets the coin is supposed to receive special blessings and luck in the coming year.
Now, if you want to talk about Pascha, THEN there'll be a lot!!!
Blessings!