Fun at the shop... your favourite practical jokes.
We often get dry ice to shrink bearings and make them fit and since we always have extra, and because boys will be boys, we have a mortar that uses dry ice as a propellant.
The dry ice pellets are typically put in a 500 ml pop bottle with a little water, dropped in the mortar (a long steel pipe) and all manner of things get dropped on top of that... we have pipes that also accomodate two litre bottles.
The launches can be quite impressive and explosive... we're talking 300 feet of altitude with 2 litres of propellant but the 500 ml bottles also make a hell of a bang.
We also have a good deal of packing material like foam pellets that look almost identical to the dry ice pellets which is important...
Imagine the reaction of our apprentice millwright when one of the guys approached him with an open pop bottle full of water and what he thought were dry ice pellets... looks like some fun right?
Imagine his reaction when the fellow with the bottle screws the lid down and quickly jams the bottle in the pocket of the apprentice's coveralls and runs like hell.
The panic was such that the young fellow couldn't extract the "explosives" from his coveralls so then he proceeded to set a new speed record for getting out of his coveralls and he too was running like hell.
This beats tying people's coveralls in knots by using the crane and some of our weightier machinery although that too is pretty funny.
My LBS likes to "antique" employees while they are in the bathroom. The bathroom is a little coat closet sized room. They line the bottom of the door way with lots of baby powder and then turn the air compressor on and spray the heck out of it....it is pretty friggin funny! You know when you are in there and you hear the air compressor kick on that you better either finish quickly or figure a way to block to gap at the bottom of the door!