The phenomenon of always having to urinate more urgently and frequently when watching a movie at the cinema.
Although often thought to be caused by drinking too much soda due to eating popcorn, movie bladder has also been noticed when the subjects have drunk neither soda nor water while watching the film.
It is possible that the combination of a dark environment, watching fictional people's lives and sitting stationary for a long period of time acts as a diuretic, thus causing movie bladder.
It can be controlled, although not always prevented, by limiting intake of liquid for the duration of the movie and for an hour or two beforehand.
Man, I got movie bladder so bad in Star Wars
that I had to leave to go pee and I totally missed the scene where Darth Vader revealed that he was Luke Skywalker's father!