Based on the movie....
"Police investigating the stabbing of a teenage girl in Westfield said she was injured during a prearranged fight involving seven other girls. Westfield police told The Republican newspaper that a group of girls from Westfield and another group from Springfield confronted each other at a playground Thursday night. A 15-year-old girl was stabbed in her arms and legs. Police said she is being treated at a hospital for wounds not considered life-threatening. Authorities said the girls decided to ‘‘square off’’ against each other. What sparked the fight was not disclosed."
Updated for the 21st century(?), of course....