Mine favourite moment of the Simpsons is when Homer and Bart went to a backstage of rock concert and Homer said: "Rock´´n´Roll and smashed a guitar!
Sparrow X
I've got one, its from the episode where Homer is trying to gain weight to get disabilty, and Bart helps him out and, finally,starts looking at Homer as a rolemodel. He has a flash forward to his future where he's one of those morbidly obesese people sitting on his bed, naked, with a group of photographers taking his picture, and he holds a stick with a rag on it and says in a very dopey hickish voice, "I wash myself with rag on a stick."
Holy Crap! That was the first thing that came to my mind! Other than that, just about every moment from the Cape Fear episode is a winner: Homer in the movie theater, driving through cactus patch, Homer trying to learn his new name, etc.