The Sound of Grampa is a song played at the end of "Lady Bouvier's Lover". It is a parody on Simon & Garfunkel's "The Sound of Silence", in a parody of the ending to the ending of the movie, "The Graduate".
Hello Grandpa, my old friend.
Your busy day is at an end.
Your exploits have been sad and boring.
They tell a tale, that's worth ignoring.
When you're alone, the words of your story will echo down the rest home hall.
Cuz no one at all
Can stand the sound of grandpa.