In one scene (while holding a baseball bat), Morgan Freeman says "They used to call me Crazy Joe. Well now they can call me Batman!" Years later Freeman would play the character of Lucius Fox, ally to Batman, in Christopher Nolan's Batman trilogy.
When the superintendent is discussing who to hire as the principal with the Mayor, the Mayor asks "What was last year's score?". The Superintendent answers "38%". Later, when Joe leaves the stage after expelling the bad students, there is a chart that shows that last year's score was 30%.
The practice exam booklet reads "New Jersey Minimun Basic Skills Tests"...probably the last place the school board (or the film's producers) would want a spelling error.
Dr. Frank Napier: [speaking to Clark]
Brother, I will go through the... fire with you! But you are not taking over. This shit you're pulling now, you've just gone plain loco!
Leonna Barrett: [as the crowd is chanting "FREE MR. CLARK"]
Listen to me! People, please! You must all disperse and return to your homes! Your presence here is helping no one! Why don't you use your brains and listen?