I remember seeing Jaws when I was 12 or so. Saw it at a boardwalk theater in Ocean City, NJ no less. Yes, it was freakishly creepy and yes, people were not going in the water nearly as much.
For R rated movie, I remember Rollerball, the first movie I ever saw on this thing called Home Box Office. This crazy brown box you hooked to the back of the tv with a long wire and a row of mechanical buttons on the other large brown box "remote".
You could jam two buttons down together *just* right and unscramble the channels you werent paying for... shhhhhhhhhh dont tell anyone.
Almost as fun as using an old UHF TV dial these days to tune in cell phones. shhhhhhhhhhhh