Has anyone ever heard these things being called baubles? That's a new one to me. Perhaps I'm just a bit uncultured! Either way, you can get some free "baubles" from the Nintendo UK store if you make a purchase of £100 or more!
Really isn't that alien an expression at all - A bauble is a Christmas decoration usually, as Bmorri says, shaped like a ball.
"Bauble" is much more of a British term than an American one. "Ornament" is much more common a term in the US.