Trivia: John Travolta made up the "cool dude walk" that Danny uses in the first scenes of filming trying to create a bad boy image.
Trivia: 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.
Trivia: When a group of waitresses at the ice-cream parlour watch the National Dance Off on television, one of them says, "There's Danny and Sandy". This waitress is John Travolta's real-life sister, Ellen.
Trivia: In the stage shows before Grease was made into a film, Jeff Conaway, who plays Kenickie, played Danny and John Travolta played Sonny. Richard Gere also auditioned to play Danny in the movie, but John was given the part because of his role in 'Saturday Night Fever'. Also Didi Conn, who plays Frenchy, wanted to play Rizzo.
Trivia: Dinah Manoff (Marty) was the only main cast member who was of high school age during filming, she was 18.
Trivia: 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.
Trivia: During the song "Look at Me, I'm Sandra Dee", Rizzo (Stockard Channing) goes to a photo of Elvis Presley and sings, "Elvis, Elvis, let me be." This shot was actually filmed on the same day Elvis died.
Trivia: At the end of the group dance when Danny and Cha-Cha get the trophy, you can see Marty fall and she is unable to get up because she keeps stepping on her dress.
Trivia: Towards the end of the film, we see a group of students rushing out of Rydell High and onto the fields for the Graduation Carnival. All of these 'students' were winners of a contest which producer Allan Carr had organised and director Randal Kleiser chose the graduation scene as the right moment.
Trivia: During the dance, Danny is shown dancing with Sandy and singing a portion of the song "Those Magic Changes." Sandy then says he's very good and that he should take singing up professionally. This is a reference to the fact that John Travolta played Doody on Broadway before going on to play Danny in the movie. (Doody sings "Those Magic Changes" in the stage version. The song was used as a dance number in the film).
Trivia: During the dance, Marty, the girl in the green strapless dress, is talking to the TV presenter next to the camera or something. Just at the end of the scene, she turns, and you can just see the top of her dress fall down quickly. It's only for half a second, so you have to look really carefully.
Trivia: The film that Danny and Sandy watch at the drive-in features Dean Martin and Jerry Lewis. Lewis was one of director Randal Kleiser's teachers at the USC in Film Directing.
Trivia: When grease lightning has just won the rally, the water in the place was really polluted and when Kenickie runs through you can see him really afraid of the water and almost tip-toeing through it.
Trivia: In the scene when Danny and the rest of the gang are in the ice-cream parlour, Rizzo is sitting at Danny's table and there are hickeys on her neck. The hickeys you see were actual/real ones.
Trivia: After Cha-Cha and Danny win the dance-off, and all the group including extras group together for the big finale and ending of the song, look for the girl in the green dress behind Vince Fontaine. As everybody gets up, her partner slyly kisses her foot and she laughs.
Trivia: In the pep rally scene where everyone is rushing up to see what Coach Calhoun has to say, you can see a brown-headed girl rush forward, and then you can see a hand reach out and pinch her bottom.