Have you ever seen a movie that bad on purpose? Maybe you and your friends really are daring each other to watch the worst possible movie you can find at the video store, because sometimes that happens -- I'm pretty sure that's how I ended up watching Children Shouldn't Play With Dead Things. (Choice quote: "I peed my pants!") Or maybe we were drunk. I don't know. It was college. But others, like Pootie Tang, became instant favorites. It's a crapshoot, so to speak. Or maybe you're just that, well, unsober (ahem) that you end up watching them with friends who insist that, no, it's really an unappreciated comedic/experimental/horror gem and you'll totally get it, man, so just have another beer (or whatever) and watch it already!
Some of my "holy *!&#!, what am I thinking?" movies include How High, Castle Freak, Super Troopers (I know, this is a touchy subject -- I plan to revisit it in the future), Bones, Mother's Day, Feed, and feardotcom. There are plenty of others, I'm sure, and some I even watched all the way through. In fact, I'm sure that I watched all of the above all the way through except for Super Troopers. Sometimes I want to know if a movie is really just that bad... And it usually is.
The "so bad they're good" cliché only goes so far. Sometimes, movies are just so bad. And then I don't know what to do. Turn it off? Stick it out? Take a nap? Make an awesome documentary about it, like Best Worst Movie? What are your double-dog dare movies? How did you end up seeing them, and once you realized how bad they were, did you turn 'em off?