When it was revealed that Anthony Edwards wasn't going to be in the third movie because he was busy shooting "some medical show in Chicago", the response from the cast was, "They make one of those every year in Hollywood. Why's he wasting his time?". The show that Edwards was busy making was ER (1994), which went on to be a big hit.
The only Nerds film in which Booger doesn't belch.
The only nerd who is never seen or mentioned is Ogre from the first two films, but he makes an appearance in the fourth film.
The trailer for this film featured the song "Hip To Be Square", by Huey Lewis and the News, from their 1986 album "Fore!". However, the song does not appear in the film itself.
The car Harold and Ira are riding in a Volkswagen Thing ( Type 181)