4. "Principal Skinner & Mrs. Krabappel Were In The Closet Making Babies..."
http://www.youtube.com/watch?v=g9MTejMEUJU&t=1m32s The Episode: Season 8, Episode 19 (Grade School Confidential) The Gag: Bart opens the janitor's closet to find Principal Skinner and Mrs. Krabappel making out, leading to a city-wide game of Chinese whispers, where the description of the events gets more and more outlandish and inaccurate. This culminates in Ralph telling his dad, "Mrs. Krabappel and Principal Skinner were in the closet making babies, and I saw one of the babies, and the baby looked at me." This of course leads to Chief Wiggum informing Superintendent Chalmers, and is a testament to how anything a kid says should be taken with several very large grains of salt.