"Merry Christmas to all..."

"... and to all a good night!" 

Retro Review: Simpsons Roasting on an Open Fire

Or the One Where: The Simpsons learn the true meaning of Christmas after adopting former racing dog and fellow lovable loser Santa's Little Helper.

The Setup: After Bart gets a tattoo, the family Christmas money is spent getting it removed, forcing Homer to go to great lengths in order to assure a merry Christmas for his family.