An extract of a letter by Grace hopper detailing the first ever computer bug
In the summer of 1945 we where building Mark II; we had to build it in an awful rush - it was wartime - out of components we could get our hands on. We where working in a World War 1 temporary building. It was a hot summer and no air conditioning, so all the windows where open. Mark II stopped, and we where trying to get her going. We finally found the relay that had failed. Inside the relay - and these where large relays - was a moth that had been beaten to death by the relay. We got a pair of tweezers, very carefully took out the moth, put it in the logbook and put scotch tape over it.
Now the commander had a habit of coming into the room and saying "Are you making any numbers?" We had to have an excuse when we weren't making any numbers, we told him that we where debugging the computer. This is where it started.
Full story and pictures here.