Homer at Troy Maclure and Selma's wedding.

"Na-na-na-na-nah-HEY!"
And the jury duty episode:

Principal Skinner: "I know you can read my thoughts, Bart. And if I find out that you cut school, your head is mine."
Homer: "And I know you can read MY thoughts, boy. Meow-meow-meow-meow-meow, Meow-meow-meow-meow-meow, Meow-meow-meow-meow-meow."
The episode on Lisa's Wedding:

Chief Wiggum: "And behold, the legendary two headed hound born with only one head! Ooh. And what have we here, the fabled Esquilax, a horse with the head of a rabbit and the body...OF A RABBIT!"