What's the Worst Movie You've ever seen?

After watching a History of Violence the other night, a movie that I think might make my top 10 worst movies ever, I started to think, what is the worst movie I've ever seen? It's a tough one. I have seen Plan 9 From Outer Space, but it's so campy, it's kind of enjoyable. There are other remarkably bad movies I've seen as well. Big Top Pee Wee, Bio-Dome, Speed,and Death Becomes Her all come to mind. As does Armageddon. Zoolander is the only film I've ever walked out of the theatre on. I really didn't hate Showgirls that much, but htat probably says more about me than it does about the movie. But I have to say that the most melodramatic load of horses*** I've ever seen is Twister. It followed every cliche ever offered up by a Hollywood film. I mean there were bad guy tornado chasers in this film, and they drove black vans. The dialogue was fingernails on a chalkboard excruciating, just one pathetically unfunny one-liner after another, interrupted by the bad storm chasers saying really mean things and two peole falling in love with a ferocious twister in the background and one of the characters dealing with the fact that her dad was killed by a tornado. Man, I hate this movie. Anyways, I want you guys to let me know what your least favorite movies are. I might even try to watch a few of them.