Jonathan Ke Quan, who played Data, wasn't allowed to swear. Sometimes parents have more say than the director. So, doing his best to satisfy both parties, he spelled it out…which is why you hear him yell, "Holy S-H-I-T" in the movie. Hey, free spelling lesson. (Source)

John Matuszak, the guy who portrayed Sloth, had a very good reason for having those massive arms and overall intimidating frame—he'd been a professional football player. For this film, he traded in his Oakland Raiders' jersey for a Superman t-shirt. (Source)

A lot of the kids' parents who show up at the end of the movie are the child actors' actual parents. Talk about being hands-on with your kid's acting career. (Source)

Sean Astin, who played Mikey, was given the treasure map to keep after filming wrapped. His mother, Patty Duke, thought it was trash and pitched it. (Source)