Trivia: When Arnie and Leigh discover that the car has been trashed at Darnell's Garage and Arnie suddenly turns on Leigh, yelling at her and shoving her backwards, note the look of shock on her face - it's real. Keith Gordon (Arnie) explains on the DVD that in rehearsing the scene, he purposely didn't react as violently, so when the scene was shot, his behavior change actually shocked Alexandra Paul (Leigh). (00:57:20)
Trivia: Reportedly, the films uses of the f-word were added at the last minute because they didn't think the film would get an R-rating due to most of the violence being not very bloody. (Mostly just people getting hit by cars.) They were worried movie goers wouldn't go to see a Stephen King horror movie that was rated PG, so they peppered in several f-bombs to artificially drive it up to an R-rating.
Trivia: One time Alexandra Paul brought her twin sister Caroline to the set and successfully pranked director John Carpenter by having Caroline shoot a scene. Carpenter, very amused, later said he could tell there was something odd going on when they shot the scene... but couldn't quite figure out what it was.