A brass ring is a small grabbable ring that a dispenser presents to a carousel rider during the course of a ride. Usually there are a large number of iron rings and one brass one, or just a few. It takes some dexterity to grab a ring from the dispenser as the carousel rotates. The iron rings can be tossed at a target as an amusement. Typically, getting the brass ring gets the rider some sort of prize when presented to the operator. The prize often is a free repeat ride. The phrase to grab the brass ring is derived from this device.
Brass ring devices were developed during the heyday of the carousel in the U.S.—about 1880 to 1921. At one time, the riders on the outside row of horses were often given a little challenge, perhaps as a way to draw interest or build excitement, more often as an enticement to sit on the outside row of horses which frequently did not move up and down and were therefore less enticing by themselves. Most rings were iron, but one or two per ride were made of brass; if a rider managed to grab a brass ring, it could be redeemed for a free ride. References to a literal brass ring go back into the 1890s.
As the carousel began to turn, rings were fed to one end of a wooden arm that was suspended above the riders. Riders hoped that the timing of the carousel rotation (and the rise-and-fall motion of their seat, when movable seats were included in the outer circle of the carousel) would place them within reach of the dispenser when a ring (and preferably a brass ring) was available.
Another system had mostly steel rings of no value and one brass ring, and a target into which the rings were to be thrown (for example the Santa Cruz Beach Boardwalk Looff Carousel uses a clown target shown in the photo above, and the Knoebel's Amusement Resort Grand Carousel uses a lion target), discouraging retention of the rings as souvenirs.
Cultural references 
"Grabbing the brass ring" also means striving for the highest prize, or living life to the fullest. It is not clear when the phrase came into wide use but has been found in dictionaries as far back as the late 19th century.
Brass ring carousels today 
Although there are a lot of carousels extant, only a handful of carousels still have brass rings. The following pre 1960 vintage carousels in North America have operating brass ring dispensers/targets:
- Information from "Carousel Info Page". National Park Service. Retrieved 10 October 2006.
- From the Brooklyn Daily Eagle of 24 September 1899 about the famous Coney Island amusement park:
- "This big place has been the rendezvous for thousands of children who have spent their nickels and have enjoyed a ride on the ponies, besides trying their best to capture the brass ring, which the boy drops in the big iron arm that is swung out at the side of the merry-go-round."
- Adam Sandy. "The Grand Carousel Knoebels Grove- Elysburg, Pennsylvania". Archived from the original on 30 June 2008. Retrieved 10 October 2006.. Images from that site: grabbing the ring and the target
- From "The Mavens' Word of the Day - Brass ring". WORDS@RANDOM, Random House, Inc. Retrieved 10 October 2006.:
- "Merriam-Webster's 10th Collegiate defines the metaphor and dates it to 1950. Christine Ammer's The American Heritage Dictionary of Idioms says it's from the late 1800s."
- World Wide Words: Brass ring
- For example: "Grab the Brass Ring". Amazon.com. Retrieved 10 October 2006.
- For example: "The Brass Ring". Amazon.com. Retrieved 14 April 2008.
- "Classic Carousels with Operating Ring Machines". National Carousel Association. Retrieved 26 September 2006.
- National Carousel Association