Freddie Prinze Jr. and Matthew Lillard appeared together again in the Scooby-Doo movies, as Fred and Shaggy. Those movies also featured Sarah Michelle Gellar (mentioned in another trivia item here) as Daphne.
The character "Brock Hudson" was actually named after a real-life student of the same name at St. John's School in Houston, Texas, the same school where Rushmore (1998) was filmed. Screenwriter R. Lee Fleming Jr. went to this school, along with Wes Anderson (director of "Rushmore") and Will Wallace, where the phrase "what kind of name is Brock Hudson?" (used twice in this movie) was commonly heard.
Girl (Sarah Michelle Gellar) is sitting in Cafeteria and speaking with Man, but in next shot when Derek Funkhouser Rutley (Chris Owen) is eating dirty pizza, the Girl has disappeared.