Last year, John T. Spencer began a great Twitter hashtag called #saidnoteacherever.
I brought together a collection of them at A Sampling Of The Best Tweets With The #SaidNoTeacherEver Hashtag.
Now, some teachers have done a short video person — unfortunately, without giving credit to John and the original source. But it is pretty funny. And if you go to watch it on YouTube, people have made some pretty nice additions in the comments.