Wizards of the Coast has been doing special holiday promo cards for their staff for several years now. They are silver-bordered, meaning that they're not eligible for tournament play. That doesn't stop people from being funny and sticking them into their casual decks or cubes. Some Commander playgroups even allow them, based on how they play.
While the Holiday promos are always worded in ways that you would never see on a tournament-legal Magic card, Goblin Sleigh Ride is more whimsical than most. I mean, first of all, you actually have a creature CLIMB onto it, even though it's a SORCERY. Then you SLIDE THEM ON THEIR MERRY WAY! Here's where it gets really fun. If that creature STAYED ON, it deals damage equal to its toughness to each other creature touched during the slide.
OK, first of all, how exactly does this sliding occur? Do you sort of fling it across the table. Do you attach it to a remote-controlled car? And how do you determine if the creature stays on? What legal ways can you fasten the creature to it? The rules nightmare here is beyond reason... obviously, that was sort of the point. But seriously, if Goblin Sleigh Ride isn't the most whimsical holiday promo card yet, and there have been quite a few of these already, I don't know what is!