For some (crazy) reason, Boomerang Brazil aired the Christmas special yesterday. It's another great episode and kinda Velma-centric (which I loved).
Some little spoilers: It's set in London, 1834-ish (it's a little confusing at first, but you get used to it). Besides Scrooge, the phantoms of past, present and future also visit Velma. There's a cute flashback scene from the time she first met the rest of the gang. The phantoms try to convince her that she's wasting her genius mind and time with mysteries, while she could be doing big discoveries and inventions.