One time, I was writing a driver while the hardware engineer (his nickname was "Hoppy") was simultaneously debugging the hardware. I kept getting a particular error condition, only to find out it was because Hoppy had been screwing with something. After a few iterations of this, I simply put a printout at that point in the code that said "Hoppy's playing with the wires!" Sure enough, I forgot to remove it, and that message popped up in the field.
"Shut 'er down, Slim, she's sucking mud!" (a favourite of my friend, Ron Eirtle)
And my personal favourite: "I can't get a buffer to save my ass!"