Harry Potter and the Chamber of Secrets is the second shortest book, but it's the longest Harry Potter film. Oddly enough, Order of the Phoenix is the longest book, but the second shortest film. (Source)

Rupert Grint is actually terrified of spiders in real life and has never watched the entire scene where he and Daniel Radcliffe are in Aragog's Hollow. We're with you there, Rupert. (Source)

The actress who plays Moaning Myrtle—Shirley Henderson—was actually thirty-seven years old at the time of filming. Sure Myrtle's ghost was fifty years old, but Myrtle herself was still supposed to be a Hogwarts student. (Source)

Sadly, Richard Harris, who played Dumbledore, died a few weeks before Chamber of Secrets was released. He was replaced with Michael Gambon in Prisoner of Azkaban. (Source)

J.K. Rowling has stated that Gilderoy Lockhart is based on a real person. She said that she had to endure knowing this guy for two solid years and that she "barely exaggerated" his personality. Here's hoping you never run into him. (Source)