During the opening credits, the binary code that scrolls by is actually the text from the opening credits in binary code.
Extras were always in short supply. So short, in fact, that for some shoots (shot after school at Cadillac High School), students were pulled out of the hall to play extras.
During the scene in Mr. Findlay's classroom, the actor who played Mr. Findlay actually read from cue cards hidden on the set, because he couldn't memorize his lines.