In a move that would have radically changed the movie, The Voyage Home was originally set to feature the great Eddie Murphy. Murphy ultimately turned down the role because, as a true fanboy, he just wanted to play a Starfleet officer. His part was rewritten and became Gillian Taylor. (Source)

An early draft of the script featured the crew's Klingon ship flying over the Super Bowl. That would have been some halftime show. (Source)

Remember the scene when Chekov asks passersby if they know where to find nuclear "wessels"? This scene was shot with hidden cameras to give it a "cinéma vérité" feel. In addition, the woman who responds to Chekov wasn't actually supposed to say anything, but the filmmakers liked the moment so much they left it in the film. (Source)

When he first joined the original Star Trek series, George Takei (who plays Sulu) was skeptical of its chances for success. And why? He thought that it was too high quality. We've seen enough long-running bad TV shows to know that the dude wasn't entirely wrong. (Source)

The rude punk rocker is Kirk Thatcher, one of the film's producers. The filmmakers even wrote the song he plays and gave it a lovely title: "I Hate You." (Source)