Every Fall, the 5th grades at my school did a study of the horror genre. Not Stephen King or Saw or anything, more like Scary Stories to Tell in the Dark, etc. Kids also would write a horror piece at the conclusion of the unit. Some years in, it occurred to me that it would be a great opportunity to target genre conventions and story structure, so the teachers and I planned a "Horror Film Fest." I scoured the 'net looking for short films that fit the genre but that didn't end up with someone in a bloody heap or anything graphic! We ended up holding "screenings" where a group of kids would come and view their assigned clip, and we'd analyze it using a story grammar (Marker) organizer and list horror elements that were in the clip ,using a concept map as an idea bank. The following week, the students would "present" the clip to the class with a descriptive teaser, using character-setting-kickoff and no spoilers and then explain why the clip fits in the horror genre. It was always a lot of fun, even though we'd always get a few "that wasn't scarrrrry..." annoying comments (quickly squashed).
I'm sure by now there are more clips out there, but here are some that we used:
Devil's Tramping Ground (I'd use The Banshee and Maco Lights)
The Big Bed
Thriller (just the opening scene)
Enjoy, hopefully these might make a fun and motivating story structure lesson for you (oh, I mean scarrrrry!!!)