A pumpkin is prominently displayed in a close-up. (Fun fact: Most of the pumpkins in this movie are made out of styrofoam and/or did not get paid.)
You spot a classic (or cliché) horror villain, like the creepy little kid, the werewolf, the sinister shut-in, or the bag of candy you bought for the children but are going to eat in one sitting.
The movie is shot in Spooky VisionTM, where we get to see through the eyes of the bad guy. Spooky VisionTM is one of the great movie techniques, right up there with Off-Screen Hand GrabTM.
You spot Sam (a.k.a. that pumpkin head kid) just creepin’ around. [SPOILER ALERT: at one point in the movie he’s on-screen for like 20 minutes, so you might as well just finish your beer/finish your candy corn.]
You notice a character from one story in the background of a different story. Like that time I saw Jack Black in Demolition Man and it just BLEW MY MIND.
Someone says “Halloween.” OK, so this rule is a little obvious. But we were pretty drunk off candy corn at this point.
There is a surprise twist! For example, you always thought that the name of this movie was Trick OR Treat, but it turns out it’s a werewolf.
If you recognize an actor that was in a comic book movie, yell out the name of that character! (For example, when you see Anna Paquin, yell “Rogue!” ) Any non-nerds that can’t name the movie you’re referring to must drink.
Take a swig of Apple Pucker whenever you notice a sucker on screen. Double drink if it’s used to murder someone! [insert “candy is bad for your health” joke here]