So bad that it's good

I saw this movie years ago in a movie theater when it first came out. I went with my brother and there were also just about another 8 or 10 people in the theater. When the lead actress was possessed by some demon in her psychiatrist's office the acting and special effects were so bad and cheesy that i started laughing out loud and could not stop for about 10 or 15 minutes. My brother was so embarrassed by my laughter he moved a couple of rows away from me but i saw i had even had him laughing. This movie is horrrible but very entertaining since it's so bad. I think it ranks up there with the brain that couldn't die and plan nine from outer space as some the most entertaining bad movies ever made.