A couple weeks ago I had the great pleasure of taking two teenage girls to see Psycho for the first time. On the way there they were doing their teenagerly duty of complaining about being dragged to see some dumb old movie. In black and white yet! (They were lying of course because a month or two ago I took the same pair to see Vertigo, so they knew this one would be good too).
Then we were watching it and they were holding onto each other for dear life, taking turns burying their heads in the other's shoulder when it got really scary!
I've read that Psycho changed the way people watch movies at the theater in that the advertising campaign said no one would be admitted after it started. Before that, you strolled in whenever.
http://www.youtube.com/watch?v=Q7vYhtfNM9U