It is a timed event where there are 4 barrels set up in the arena in a square. You and another horse and rider must hold a brown gunny sack between you as you complete a full circle around the barrels. Most places allow you to do a practice run before your time starts. The time starts usually on the side of the square pattern right by the crow's nest. If you or your partner drop the sack before you complete a full circle, you are disqualified. The fastest time wins!
This first one is from July 2007. My mother and I did the sack race together and we took first place on this day. I love this video with the train in the background.
This second one is actually from the same show but the next year in June of 2008. My mom's horse had foundered so I ran the sack race with two different people this year -- neither of which had I ever done the sack race with before! The first lady I ran with we took 4th place just out of the money, despite a rocky first turn (we smacked together pretty good if you watch!). But her horse can book it and she's a great rider. If we would have tightened up our last turn, we probably would have squeaked into 3rd, but it was tough competition. Also, I love my mom yelling in the background, haha.
This third one if from the same day, but just a few riders later! I did this with a good family friend and this little cowgirl can ride! And her old 25-year-old pony mare can RUN! The duo of the big horse and little horse took FIRST PLACE with a smokin' run! Which is ironic because my horse actually hated her horse, but they seemed to work well together!
Maybe I like this event so much b/c you get to haul it full speed around the arena!