Sudden Death Karaoke
The prank played by drivers and shotgun riders on the rest of the car. The secret Sudden Death Karaoke signal is when you lean over and turn up the radio and raises one eyebrow. Then, once everyone in the backseat is singing horribly offkey and attempting to drown out the too-loud song, the front seat riders (immediately and without the knowledge of the back seaters) turn off the song and revel in the embarassment of the horrible singers who know at most 3/4 of the words. See also Cars, Karaoke.