Science Teacher: You know what glue is made of, don't you?
Student: Sure. Everyone knows.
Science Teacher: Okay, what is it?
I imagined every kid who had eaten glue in elementary school paused for a moment when they overheard that conversation.
This science teacher is swift, though. He had the presence of mind to ask the students to "hold on to your spherical objects". You learn that lesson, pretty quickly. However, it does ruin the opportunity for your fellow colleague to utter "that's what she/he said" and so you simply swallow it and make the boss happy... That's what she said.