Chalkboard: The capital of Montana is not Hannah.
Couch: A repeat of the couch gag from "The Ziff Who Came to Dinner" and "On a Clear Day, I Can't See My Sister" where, in a parody of the science short film Powers of Ten, the camera pans from the couch scene to the house, the city, the world, the galaxy, outer space, and back to Homer. Unlike the previous two versions, Homer says, "Weird!" instead of "Wow!" or "Cool!"
(Grampa suggests that Homer should go see Professor Frink to help him remember what happened the night before.)
Homer: Really? Oh, that's great, Dad. How can I ever repay you?
Grampa: Punch that orderly who takes sips out of my juice.
(Cut to Homer punching an orderly who is about to make a bed.)
Grampa: No, wait. That's the guy that saved my life.
(Homer seeks Flanders help to find out what happened to him.)
Homer: Flanders, why did you call the cops last night?
Ned: I had to--I heard a hubbub, Bub.
Homer: What did I do?!
Ned: Well, I can't say for sure, but as a Christian, I assume the worst.
Homer: Dad, I can't remember what I did last night. Do have any idea?
Grampa: You come to me for help rememberin'? That's like asking your horse to do your taxes--Which I did in 1998. (Shows photo of horse using an adding machine.)
This episode's title is adapted from 'Eternal Sunshine of the Spotless Mind', a 2004 romantic comedy starring Jim Carrey, Kate Winslet, Kirsten Dunst & Mark Ruffalo