In Japan, there's a weird tradition of eating KFC (yes, Kentucky Fried Chicken) as the Christmas meal. I'll pass.
But there are also these things called "enkai" which are basically parties with coworkers. My school usually has one after special events (culture festival, end of semester, sports day), so I might go if there's one for winter break. They're expensive, though, at 5000 yen (50 USD) per person.