A Chinese fire drill is a dangerous prank, or perhaps just an expression of high spirits, popular in the United States during the 1960s. It is performed when a car is stopped at a red traffic light, at which point all of the car's occupants get out, run around the car, and return to their own (or other) seats. Chinese Fire Drills are sometimes executed when one needs to get something from the trunk of a car.
The term is also used as a figure of speech to mean any ineffective and chaotic exercise. It comes from a British tendency around the time of World War I to use the adjective Chinese as a slur, implying "confused, disorganized, or inferior". Today the expression may seem to have lost much of its insulting meaning and many people say it without realizing the offense it might cause to others.