1) White Chicks
I've written about this film being my guilty pleasure before. I had a nice time seeing this with friends in high school and I still love it. I don't care how terrible it is. I will laugh at Terry Crews in this movie for the rest of my life. "Eaaasssssy White Chocolate."
2) Sleepaway Camp
I love campy horror films. This film is pretty terrible, but the ending is actually really surprising. I didn't see it coming at all. I think I was 14 or 15 when I saw this. It's all over the internet, so even if you haven't seen it you probably know it. Still, it's something else.
3) The Room
I participated in this "So You Think You Can Review" tournament over at The LAMB about four years ago. Two people were given the same movie to review and people voted on who they thought wrote the better one. I was given The Room, (and shockingly advanced to the 2nd round with this thing) I watched it sober, and hated every minute. I mused towards the end that this was probably better under the influence, and I was right. Watching it again with a few beers and a few friends made this movie hysterical. Now it's hysterical to me with or without booze. It's SO FUCKING BAD. You have to see it.