Some amusing one's courtesy of my father, who worked in glass blowing labs (building vacuum valves for early computers) before graduating to drawing offices in both the aircraft and oil industry.
1) Every Friday afternoon, the glassblowers used to spend their lunch hours making syringes, before going on an Unreal Tournament style frag-fest around the store-room soaking one another. Anyway, one chap is surrounded so he darts behind a shelf and squats down to avoid the watery onslaught, right onto a large bucket full of freshly blown vaccum valve cases. Because the sharp points at either end of the valves had yet to be nipped off, the needles of glass embedded themselves in his behind, thus requiring hospital attention.
2) After taking a job with Handley Page, father is working his first day and decided he needs the bathroom. He asks the manager where the gents is, and he replies in a strait-laced manner. My dad made his way to the lavatory, sits down and starts to think "Strange, this place looks like it hasn't been used in yea........." just as a Victor bomber starts engine (x4) trials on the other side of the lavatory wall. Four Rolls Royce Conway engines make for a magnificent laxative so I'm told.
3) One of the co-workers in a drawing office had a reputation for spectacular flatulence and is able to perform vividly on command. His ego is dented when a rival appears with equally impressive sphinctoral abilities. War is quickly declared, with a contest to be held at noon on the next Friday. Both parties go into intensive training, one of which spent the week eating raw onions and chilli peppers. Friday noon dawns and the protaganists face each other. The winner of the toss goes first, grasps a drawing board, and with his face turned red through straining immediately craps himself.
4) The most evil act of all concerned an unfortunate chap with chronic piles. Every lunchtime he used to make for the gents carrying a tube of Preparation H. However one assailant squeezed all the contents out of the tube before refilling it with Sloans Heat Rub. The resulting screams were heard throughout the entire building.