My Little Pony - Winter Wrap Up (DJ Amaya vs. Groovebot Extended Vocal Club) is a remix of something of a remix classic, and even better.
Gotye - State of the Art, a typically richly layered piece, of a mildly dark nature.
And just in case you've not seen it yet, one of my old favorites - Chage & Aska - On Your Mark. It's a good track anyway, but then Studio Ghibli worked their magic in providing a complete story in their usual luscious animation style, in six minutes. (There doesn't seem to be an HD version of any kind, unfortunately, though if you know otherwise, please shout!)
Hope everyone's having (or has had) a wonderful time, whatever you're celebrating - it's the company that matters. And the food. =:)