I well remember "An Unlocked Window" as one of the most terrifying experiences of my life. I watched this television show about two nurses, an invalid and a serial killer on the loose while sitting in our family den. My father was laying on the couch. The atmosphere of the story really pulled you in, and my heart was in my throat the entire time.
At one of the crucial moments in the story, our family cat jumped up on the window sill from outside. I jumped. My father must have gone up in the air three feet. That night, I went to bed with a butcher knife under my pillow. If you saw this show, you may recall that the killer had this deep, growly type laugh. Well, not only was my father fooling around with that laugh, but when our dog settled down in the hall, I swear she made that same noise. Honestly I never thought I'd recover. It was worse than watching Psycho with a bunch of people in a dorm room and everybody screaming.
If you ever get a chance to see this, don't miss it, but don't watch it alone. I'm sure it's lost none of its power.