Murder on the Orient Express.
Clue. Hysterical film.
I LOVE that film.
As has been said, Tim Curry is brilliant in it.
Is the answer to this not: The Core.
This thread needs to have a few set rules. Too many people are nominating films which are not "bad" at all. May I suggest using the website Rotten Tomatoes. Where bad movies are labelled as being "rotten" if they get below 50% by a large number of reviewers.
My entry is Mortal Kombat:
http://www.rottentomatoes.com/m/mortal_kombat/
33% but for some reason I love it.
Maybe it's the Utah Saints soundtrack.
In that case:
http://www.rottentomatoes.com/mobile/m/fear_and_loathing_in_las_vegas/
Fear and loathing in Las Vegas.
How does this film have only 50%?