Trivia: Director Martin Scorsese makes more then just a cameo in this film, he's the passenger that sits with Travis talking about how he's going to kill his wife for cheating on him with a black man. He's credited as "Man Watching Silhouette".
Trivia: When Crichton talks to "Harvey" (Scorpius in his head) for the first time in the movie, Scorpius is dressed like Einstein. There is a blackboard with equations on it. One of them is "e = MC hammer". (00:21:30)