An exclamation of distaste or dislike. Originating from Homer Simpson. Actually accepted into some dictionaries (such as this one.)
<Homer> You might say he's barkin' up up the wrong Bush! Heh heh heh.
<HomersBrain> There it is, Homer. The cleverest thing you've ever said, and nobody heard it.
<Homer> D'OH!
"Marge: I don't want you stalking anyone tonight.
Homer: Oh, OK, have it your own way, Marge. I'll be backin a minute I'm... going outside. To... stalk ...Lenny and Carl. D'oh!"