John Bender (Judd Nelson)’s Timeline and Summary

Bender walks to the school for detention.
Once they're seated in the library, he mocks Vernon's clothes and gets assigned another weekend of detention.
He immediately starts harassing Claire and irritating Andrew, nearly provoking a fight.
Eventually, he gets around to telling Vernon "Eat my shorts!" and earns another two months' worth of detention.
He reveals his violent home life to the other kids, showing Andrew a scar from where his father burned him with a cigar.
Bender retrieves a bag of pot from his locker, leading the other kids with him—he ends up diverting Vernon from their trail so they can get back to the library.
Vernon tries to get Bender to hit him, so he can beat Bender up without violating school rules. Bender is disturbed and won't do it.
Bender sneaks back into the library, and they all smoke his pot with him (except for Allison).
They sit together in a group in a circle discussing their lives—uncovering revelations, arguing, and crying.
Finally, Bender and Claire make out, and seem like they're going to be together from now on.
After leaving detention, Bender walks across the football field and pumps his fist in the air triumphantly—the movie's final image.