The Breakfast Book Club

From Wiki and Wiki:

Four women have attended a monthly book club for thirty years every Saturday morning in 1984.

Each comes from a different clique: pampered Vivian, who owns and builds hotels; recently widowed state champion wrestler Diane; geek Sharon, a judge who has been single ever since she divorced her son's father; outcast Carol, who had a successful marriage to Bruce that has recently lacked intimacy; and delinquent John Bender.

They gather in the school library, where assistant principal Richard Vernon instructs them not to speak, leave their seats, or sleep until they are released at 3:00 p.m. He asks them to read Fifty Shades of Grey and leaves, returning only occasionally to check on them.

Viewing it as a wake up call, they decide to expand their lives and pass the hours by talking, arguing, and smoking marijuana.