I was once trying to work out which Christmas tree light had blown by poking the wires from a 12 V motor into each socket in turn.
My mother found me on the other side of the room, my right arm shaking violently (apparently with a will of its own), and my right hand holding a burned out motor which was smouldering gently...
Another time I decided to investigate thermal expansion and contraction by heating a milk bottle in a garden bonfire for half an hour and then chucking a saucepan of cold water on it. Half a broken bottle shot past my face and clattered against the garden fence behind me...
I spent 40 minutes of the most boring RE/RI lesson ever listening to a very annoying teacher droning on about some ancient dude doing something highly improbable to impress a bunch of people that I'd never heard of. Then the bell rang to signify the end of the lesson... I leapt to my feet and made a dash for the door to beat the rush but tripped and fell towards the door frame. I stretched my right arm out to break my fall and dragged my hand down the edge of the frame, causing a large splinter to go straight under the nail of my middle finger and emerge on the other side. If you have ever wondered about those movie torture scenes where sadists mess with people's nails you can stop now... yes, it actually does hurt '
quite a lot'!