My new favorite Christmas special is Shrek the Halls. It's silly and witty, slightly icky at times, clever and charming, and a somewhat painfully honest commentary on family interactions at the holidays.
It was on TV tonight. You may have caught it. We bought the DVD and have watched it at least 5 times already this year.
If you haven't seen it, I highly recommend it. Eddie Murphy's Donkey makes me cackle:
My mama used to always say, 'Christmas ain't Christmas till somebody cries!'