Movie Game: Spot the Rifle
My kids and I drive my wife crazy when we are watching a movie at home. We have all kinds of conversations going, conversations we would never even consider in a theater (another reason, beyond screen size and sound systems, why I consider the home movie watching experience distinct and not entirely competitive with the theater experience). No movie can be watched without a dozen IMDB lookups of what else so and so actor was in.
One game we play is spot the rifle. This probably does not mean what you think it means. It refers to Checkov's rule (the writer, not the astrogator) never to put a rifle on stage in Act 1 if someone is not going to use it in Act 3. Our game assumes that movies are following this rule, so we look for elements sometimes awkwardly thrown into Act 1 so they can be used later. Note this is distinct from a macguffin, and is really not the same as foreshadowing either. The "save the clock tower" fund raiser early in Back to the Future is an example. Calling your shot in this game, like on Jeopardy, requires the answer to be in a specific form, ie "Never put a lightening strike on a clock tower on stage in Act 1 if you are not going to use it in Act 3". It goes without saying that winning answers must be shouted out in Act 1, not Act 3.
My daughter, who is quite an aficionado of romantic comedies, texted me an updated corollary: Don't put a pregnant woman on stage in act 1 of a comedy unless she is going to go into labor at the most inconvenient moment in act 3.
Postscript: The "Q" armorer dynamic in James Bond is a version of this on steroids. The rules of Q were: 1. Every tool he gives Bond gets used and 2. No matter how odd or arcane the tool (e.g. high powered electromagnet built into a condom) it turns out to be exactly the niche tool Bond needs to escape at some point. For example, one and only one time is Bond issued with a CPR device but that one time he needs it to save his life (Daniel Craig version of Casino Royale).