A first generation freefall amusement ride built by Intamin. Very popular during the 80s, they are now obsolete - although a few examples of this still exist at parks across the USA.
Basically, the ride consists of a 4-across car, which is hauled up a vertical shaft about 50 feet, scoots forward a few feet, then drops, freefalling for a second or two. The shape of the cars, in addition to the noise they make, is where the nickname "dumpster drop" came from.
Six Flags Magic Mountain needs to ditch the dumpster drop and build a *real* freefall ride.