There are four engineers travelling in a car -- a mechanical engineer,a chemical engineer, an electrical engineer, and a computer engineer. The car breaks down.
"Sounds to me as if the pistons have seized. We'll have to strip down the engine before we can get the car working again", says the mechanical engineer.
"Well", says the chemical engineer, "it sounded to me as if the fuel might be contaminated. I think we should clear out the fuel system."
"I thought it might be an grounding problem", says the electrical engineer, "or maybe a faulty plug lead."
They all turn to the computer scientist, who up to then had said nothing, and asked "Well, what do you think?"
"I put on my wizard robe and hat. My other car is a cdr." The computer scientist pulls out a cudder from his pocket, and shoves it down the throats of the engineers. "Take that, motherfuckers!!!!"