S08E19 Grade School Confidential
Martin's birthday party is predictably dull until nearly all the guests become ill with food poisoning. The only ones not to get sick are Bart (who didn't want to eat the spoiled oysters), and Principal Skinner and Mrs. Krabappel, who fall in love with each other. Bart catches his principal and teacher kissing passionately, but they immediately find out and want to swear him to secrecy. They make...