Vend U. (The Fantasy World of Nancy Springer)

Jocelyn is a complete pest, She's constantly playing practical jokes and has no problems beating up boys. Not quite the person you want around you when you're trying to enjoy your summer art class on a college campus. When Jocelyn decides to take out her inner aggressions on the cafeteria's vending machines, it's not just the students who decide it's time to do something about the biggest bully on campus. After all, even a vending machine has feelings. Jocelyn is about to learn a very dangerous lesson. Sometimes the least healthy item in a vending machine isn't the weeks-old chocolate, but the machine itself. A short story.