What was the name of the fictional high school attended by Charlene "Cha Cha" DiGregorio, Danny, and Sandy in Grease? 
Annette Charles: Annette Charles (born Annette Cardona; March 5, 1948 – August 3, 2011) was an American actress best known for her role as Charlene "Cha Cha" DiGregorio in the 1978 feature film "Grease". Grease (film):  Written by Bronte Woodard and directed by Randal Kleiser in his theatrical feature film debut, the film depicts the life of Rydell High School students Danny (John Travolta) and Sandy (Olivia Newton-John) in the late 1950s.
Rydell High School