1) A very horrible movie, with underdeveloped and unintelligent characters, and an equally unimpressive story.
2) A movie that is painful to watch.
Popularized by the television show Mystery Science Theater 3000, where many horrible movies were refered to as "stinkburgers".
"Any movie produced or directed by Roger Corman is likely to be a total stinkburger."
"Ashton Kutcher stinks out loud... all his movies are stinkburgers."