Trivia: Two points in the movie where you can see Staypuft Marshmallows: the first is next to the eggs on Dana's worktop when the eggs start to cook, and the second is when the beam of light is coming out of the Ghostbuster's house, there is a wide shot of it and on the left of the screen there is a billboard advertising Staypuft Marshmallows.
Trivia: After the librarian signs out in the downstairs section of the New York Public Library, she passes the card catalogue shelves which open behind her and suddenly hurl their contents into the air. To achieve this effect, technicians were standing behind the shelves to push them out and then used a copper pipe to blow out the contents.
Trivia: Harold Ramis states in the DVD commentary that the "experiment" that Venkman conducts at the beginning of the film is inspired in part by the Milgram Experiment. In the Milgram Experiment, people were told that they would be giving a person increasingly powerful electric shock whenever the person incorrectly answered a question from a list that was read off. (The reality was that the person being "shocked" was an actor and that the generator was fake; the experiment was a test of whether the subject would give a person lethal shocks just because an experimenter was telling them to do so.)
Trivia: When Spengler, Venkman and Stantz are in the basement of the New York Public Library, the bookcase falls over, prompting Venkman to ask Stantz if this has ever happened before. The whole exchange, including the bookcase falling over, was not scripted. It is thought that the bookcase fell because some crewmen accidentally bumped into it, and Bill Murray ad-libbed his lines. Producer/director Ivan Reitman decided to leave it in the movie because it added to the supernatural qualities of the film.