One of my typical beginning lessons for private students and classes covers the basic development of the Giuoco Piano. We discuss how both sides make reasonable developing moves towards the center. Usually, to put a simple end to the game, I have black allow a devastating pin. His kingside gets ripped open and after one or two inaccurate moves he gets checkmated.
Today, playing an online blitz game against an opponent near my own rating, I got to put this lesson to good use. I had black, so the game isn't identical to the lesson, but once my opponent wasted a tempo with Bg5-e3, we had transposed back into my lesson, following it all the way to resignation shortly before mate.
Next time I teach this game it won't have to be between made up opponents.