Grease (1978)

Revealing: In the soda shop, the waitress turns off the lights with her elbow because her hands are full, but she misses the light switch by 6 inches.

Continuity: At Frenchie's sleepover when they are talking about piercing Sandy's ears, it shows Sandy holding the wine bottle and passing it to Jan. Then it cuts back to Sandy and she is still holding the wine, then it cuts back to Jan and she has the wine again.

Revealing: At the dance, there's a scene where everyone started dancing after Cha-Cha and Danny won the trophy. Well Marty comes in from the side of the screen and lands on the floor in some kind of split, and you can clearly see she is wearing knee pads.

Singer Olivia Newton-John had hardly done any acting, and was terrified of the idea of starring in a big-budget musical. John Travolta (who was also a singer) was really supportive though, and sometimes when Newton-John made a mistake during filming, he would make it look like it was his fault and take the blame for it.

A little bit of trivia - the Saran Wrap they are wrapping the car in during "Greased Lightning" is a blatant sexual reference (check out John Travolta rubbing it on his crotch). In the 50's, Saran Wrap was often used in lieu of condoms.

Stockard Channing was 34 when Grease was being made, and she was supposed to be playing a teenager. She was also the oldest of the main cast members.