GM: All Models, While holding second station preset down, right turn signal on, hit brake. Audio system will energize and a short welcome message from Bob Lutz will be heard, desparately thanking you for buying another unimpressive GM vehicle.
Ford: Early Explorer Models, Turn ignition to accessory, hold right and left window down switches, left or right turn of wheel will toggle odometer output from numbers to a series of skull/crossbone icons.
Thought these up yesterday, so I know this wasn't posted before. Come on folks, I'm sure we can find more...
