Thanks to the SDMB I only learned the meaning of Chekhov’s Gun several weeks ago.
In the past week I have re-watched both Die Hard and Star Trek II: The Wrath of Khan, and had “Aha! That’s a Chekhov’s Gun!” moments at the end, and beginning of the films, respectively.
In the opening scenes of Die Hard, Ellis seems to make a bit of a big deal about McClane seeing Holly’s new gift from the company, a gold Rolex. The timepiece never factors into the story whatsoever until the end, when the villain Hans Gruber is clinging to Holly’s wrist to keep from falling 30-odd floors to the ground below; McClane unclasps the wristband of her watch and Gruber loses his grip, plunging to his death.
In the opening scenes of Star Trek II: The Wrath of Khan, Spock pretends to “die” during Saavik’s Kobayashi Maru training sequence. Moments later, when Kirk meets up with Spock outside his quarters, Kirk playfully asks “Aren’t you dead?” Of course I know that Spock will die at the end of the movie.
Any other* Chekhov’s Gun* examples, from your favourite movies?