Completely Different Title: Bus Man, in Japan, albeit it was reverted recently to the original English name, after too much controversy since it's original release in Japan, since that name is a wordplay from the movie Densha Otoko (Train Man)
Dawson Casting: Most of the main cast of high school students were in their 20's or 30s, with the exception of Tina Majorino and Hailie Duff who were both about 18. Averted with the extras, played by actual high school students.
No Budget: It only took $400,000 to produce Napoleon Dynamite and nearly half of that was spent for the post-credits scene.
Throw It In: Napoleon's dancing was entirely improvised by Heder.
Also, the scene where Kip is giving the demonstration with the van and the dinnerware. Originally, he was to roll over it, and the plastic would deform but reshape itself, to which Kip was to say, "Pretty cool." However, the plastic was unable to comply due to the laws of physics, and that is what is seen in the film. It turns to be actually funnier.
Write What You Know: Jared and Jerusha Hess are from a small Mormon community in Idaho, and Pedro was based on Jared's friend.
Many of the events are also from the directors' own life, such as the cow shooting scene, the "Happy Hands" club, the "I like your sleeves" line...