Woo hoo is a catchphrase used by Homer Simpson. He uses it when he is happy. In one episode, he is seen going, "D'oh! D'oh! D'oh! Woo-Hoo! D'oh! D'oh! D'oh! D'oh! D'oh! D'oh! Woo-Hoo!" This is while a wheel is spinning around. When it gets to 17, his number, he says, "Woo-Hoo!" In another, he says it, but when Lisa protests, she says, "I said, 'Woo-Hoo,'" in the same tone.