I worked with a high school biology teacher named John Johnson (seriously). Mr. Johnson kept a long hollow steel pipe on the ledge of his wipe board. While he was teaching stimulus response, he would take the pipe off the ledge and slam it down on the tile science room floor. It scared the shit out of everyone in the room who knew he was about to do it. It literally created am ear piercing noise.
John was a good guy, but his teaching must have been what Ben Stein's character in Ferris Bueller's Day Off was based on. He was a dry dude, and when he turned the lights out and started delivering notes via the overhead projector, students occasionally fell asleep.
The student who falls asleep in class has long posed a bit of a quandary. The students basically turn on their vulnerable classmate hoping that their teacher will stop acting like an adult, lower themselves to their maturity level and pull some prank. The teacher often reverts back to their college days and begins quickly searching their mind for some gag that won't get them fired.
John Johnson went for his big pipe. With a silly grin he tip toed over to his victim, a freshman girl with little interest in the basics of cellular metabolism. Mr. Johnson hammered the pipe on the floor near the girl who nearly fell off her stool. Like I said, the noise startled you when you knew it was coming, but after the class recovered from their own shock they howled with laughter. The girl was of course embarrassed and pissed off, but what leg could she stand on when she's sleeping in class?
News spread quickly through the school of the incident. Both from students and John telling everyone who had ears (it was kind of funny... a little cruel, but still kind of funny). The problem was, John kept teaching with the lights out, kids kept falling asleep, and John kept slamming his pipe down on the floor. It became 'his thing.' You could hear the damn pipe echoing through the whole building. At first all the student in your class would giggle and you'd say something like, "Oops, looks like someone fell asleep in Mr. Johnson's class." But the first time you were walking down the hall on your plan with a cup of coffee and nearly had a heart attack because some asshole keeps tossing an steel rod around, it ceases to be cute.
John Johnson carried on with the pipe routine till he retired. I picture him sitting around in retirement telling war stories to anyone who will listen about what he used to do when kids nodded off his his 9th grade biology course, and still just thinking it was the most hysterical thing of all time.