I agree with Katie... Jingle bells is great - though they really struggle on 'dashing THROUGH the snow' - 'thr' is a really hard sound to get for French children! I teach the vocabulary beforehand for 'bells' and 'snow' and 'sleigh' etc - usually I pick 10 words. If you print the words off on big cards - say 3 of each - and the kids have to stand up with their word when they hear it. You can also get them to do a word each, round the room. Kid 1 says 'Dashing', Kid 2 says 'through', Kid 3 says 'the' and so on. You could easily spend an entire lesson doing that!! Alternatively, use the 10 words from your learned vocabulary list, give out 2 or 3 examples and then get them to stand up when they hear it or sing it. It's really cute!!
I do 'winter clothes' - take a bag of winter clothes in - ten different things, like mittens, gloves, scarves, bobble hats, coats, wellies, boots, ear muffs, jumpers (don't forget to teach 'sweater' as well as jumper!!) and umbrellas, and get a boy and a girl (preferably a naughty boy, because then he's at the front in the spotlight and gets everyone's attention on him, which is what he wants, but at the same time, he's under pressure to perform!!) and then give items to the class to put on the two 'models' - you could have a competition. The first group to find and adorn the model with a 'scarf' for example, 'a bobble hat', 'wellies' etc. They have 10 words to learn in a way that gets them moving and thinking.
I also do tasters of Christmas pudding, mince pies etc which they haven't usually tasted. They are quite familiar with Christmas pudding from the television, but they often haven't tasted it. The same with mince pies.
Hope that helps!!
Oh, and another one, get the 15 words on A6 cards for the end, get a picture of each word on a matching 15 cards, mix them up, and then ask them to find each other - the picture to match the vocabulary - nice way to finish. I get them to do it in silence, so they can't cheat! They have to go around, showing their cards to one another until they find the one that matches them. You can do this with any activity, though. It's always a good one to check the group's understanding and get them doing something at the end. Sometimes, I do the same thing with the same words at the beginning of the next session, to check their understanding.