Samuel L. Jackson had just undergone treatment for drug addiction, and had only two weeks from his discharge from rehab to the start of filming. Jackson has gone on record as saying that Gator's ravaged look was not make-up, but actually the result of Jackson's own detoxification.
During a scuffle in Paulie's store, a man can be seen reading a newspaper with a front headline that reads "Doin' The Right Thing." Most likely this is a reference to one of Spike Lee's earlier films, Do the Right Thing (1989).
Debi Mazar tells her boyfriend in the car that she wants to listen to Madonna. Mazar is a longtime friend of Madonna's, having been her make-up artist before getting into acting, and later appeared in a few of her videos including "Papa Don't Preach", "True Blue" and "Music". Mazar also threw Madonna her bridal shower, prior to her marriage to Sean Penn.
When Angie is cooking dinner for her father and brothers, she is seen wearing a Kearney Tigers sweatshirt. The Kearney Tigers are a basketball team belonging to a popular all girls high school in Bensonhurst, Brooklyn.
Three cast members go on to play Marvel superheroes. Halle Berry plays Storm in the X-Men franchise. Samuel L. Jackson plays Nick Fury in the Marvel Cinematic Universe. Wesley Snipes plays Blade in the Blade trilogy.
When Flipper resigns and Jerry and Leslie pursue him as he leaves the office, there is an exchange that goes - Leslie: "Who's gonna play third base?" Flipper: "I don't give a damn who plays third base." This is very similar to lines from 'Who's on First?', the classic Abbot and Costello skit.
Giancarlo Esposito: A homeless man picking up Flipper's belongings while his wife throws them out of the window. This cameo role also serves as another reference to Do the Right Thing (1989) as the homeless man is in fact the very same Buggin' Out character that protested Sal's lack of African-Americans on his wall of fame.
The trivia item below may give away important plot points.
Spike Lee has mentioned several times in interviews that he used the Marvin Gaye shooting incident, in which Marvin's step-father shot him, as the inspiration for The Good Reverend Doctor shooting Gator.