A very sarcastic responce meaning "Oh....Really?" but said after a stupid or unfactual comment or when you don't really care about what the other person is saying to you. Usually said with eyes 3/4 shut and mouth drooped like a dog. You know that you have used it correctly if the person laughs hysterically or shoots you a death look.
"You know...I shot an 76 last week at Pepple Beach"