Shown one weekday afternoon(i think i was ill and not at school), early 70s, it started with creepy montage of faces and had several people sat around a piano discussing how music is used in horror films(art show of some kind?), but the bit that i most remember and scared the pants offa me was a clip from Hammers Dracula where Peter Cushing rips the curtains down and shrivels up Christopher Lee. Also a clip from Nosferatu(on the ship).
