Most people outside of Calgary likely haven't heard of horse poop bingo.

The longstanding Calgary tradition sees a grid of numbers painted in the intersection of Fifth Street and Ninth Avenue S.W. every year — right in the middle of the Calgary Stampede parade route. It all started 15 years ago to keep people entertained as the parade wound its way through the city. 

"It's something we set up about 15 years ago because there was a bit of a boring time when people were waiting for  the parade to happen,"  said Rod McLeod, a 37-year Calgary Stampede volunteer. "So we went, 'Why don't we set up — we called it a poop target at the time!"

The bingo grid has 80 squares, each randomly numbered, and tickets with a corresponding number are then sold to parade watchers for $2 each. 

The first time a horse poops on a square, that ticket holder walks away with $80, an amount that's split between the winner and a charity. 

This year, the charity is one that helps support military families.

If, by some miracle, a horse doesn't poop on the grid, organizers have a bag of horse poo that they will then throw up in the air to see where it lands on the bingo grid.

Either way, someone walks away with cash.

"It's funny because when horses come in to the intersection, you'll hear people will call, 'Go over to 34, go to 32 or 25 or whatever!" said Rood. "It really generates a lot of interest in the intersection."