Thomas Gray's window

The story goes that Thomas Gray had mortal fear of fire and installed a metal bar outside his window at Peterhouse in case he would one day have to climb out. He was said to be a lazy professor while at Cambridge and would often not show up to his classes. To get even, some of his students decided to play a practical joke on him. One night, they stood outside his window with a tub of water and began shouting "Fire!!" Gray panicked, tied his sheets to the bar, and let himself down. But the sheets weren't long enough for him to reach the ground, and so he had to let himself drop...drenching himself in the process. I don't know if this actually improved his attendance, though.