We have loved reading the best shop practical jokes. Non of ours come close to your standards.
What I would like to hear is some of the worst shop disasters. Don't want to hear about people getting hurt just funny things that happen that cause destruction. These things usually require the passage of time so they only sound funny now, not then.
Such as:
Back when I was service manager we had a guy who liked to test park brakes while driving the vehicles on the PDI test drive. (I didn't know this at the time) This particular tech leaves the shop on a PDI test drive. Shortly thereafter I receive I call and he tells me the car made a lot of grinding noise and slid to a stop. I sent a wrecker and towed the car back. The next day the factory rep was in and I told him we had this problem. He insisted that we pull the wheels while he was there. Since we hadn't touched the car since it was towed we put it on the hoist and pulled the brake drums. EVERY part except the axle and the backing plate hit the floor on both sides. Needless to say the rep ran for a product report form and started writing. Only after a new axle was air freighted and an engineer had been dispatched to retrieve the defective unit did the tech fess up. Several months later I ran into the same engineer who picked up the defective piece. He looked at me a said the only way they could duplicate the failure was drive a new car (less than 5 miles on the odometer) at 55mph and yank on the park brake handle. I asked if the plastic handle slid up over the release button like ours did, thus preventing the release of the just applied brake. He said no that didn't happen. I told him the root cause had not been found. This was over 25 years ago and we tell it now and again with a smile on our faces. Even the engineer laughed.
PS - was not the lease bit funny at the time!