Too many to choose from!
I have two shoeboxes full of Christmas CDs, but the kids seemed to like WCBS-FM (local oldies station -- the CD can be found around the country with different call letters) Christmas Songs Vol 2, which not only includes Grandma Got Run Over By a Reindeer, but also, "Domenick the Donkey" by Lou Monte (he's an Italian donkey, he's not the donkey that carried Mary or anything like that) and "Donde Esta Santa Claus?", which is just fun.
Among the dumbest songs (renditions): Mariah Carey's version of "Joy to the World". What's so bad about it?
Seriously -- it's the Three Dog Night song. I'm not kidding.
You have got to see this video:)
Dominick the Donkey
http://www.youtube.com/watch?v=Ok5rOO2v2dU