Wearing a maize-and-blue helmet adorned with toilet bowl brushes, and with cans of beer chilling in his toilet tank, Dain Vettese is raring to race his Kohler toilet-on-wheels in the premiere Big Flush Toilet Race. His teammates give “The Skidmark”–as they call their gravity-powered potty–a hearty push as spectators cheer from the curb on this summer evening. Toilet paper flaps in the breeze behind Vettese as he rolls down Main St. For a few moments at least, silliness reigns in Ann Arbor.

The race is part of the annual UA Plumbers and Pipefitters Block Party, which takes place on Main St. More than 2,000 UA members come to town each year for instructor training. While they’re in town, they celebrate at the block party’s pub crawl, enjoy live music outdoors, and host a 5 km run to benefit the Semper Fi fund for wounded veterans. The Big Flush is the newest addition to the festivities–and its participants seem as serious about having fun as they do about winning.

Ann Arbor’s Randall Whitaker, unofficial Big Flush captain for UA Local 190, tied construction of the Skidmark into an apprenticeship class, and the team used four-inch steel pipe–“the same as we use in the field”–to incorporate the letters “UA” into the design. “The Brown Streak Express,” hailing from West Virginia, has dubbed its crew the “Poop Patrol,” and there’s a plunger sprouting from the pilot’s helmet. Other teams include the “Kohler Rollers” of Flint and the “Toledo Tooters.” However, it is the Canadians–two dozen strong, from �xADVancouver–who seem to demand the most attention. Dressed impeccably in matching bowling shirts and driving caps, they arrive on the scene with a sleek silver racer named “Out for a Rip, Eh?” They say it’s been several months in the making, and they’ve even set up a party tent to receive fans.

In the end, a tiebreaker gives Canada the win. After the race, the Canucks whoop it up outside Conor O’Neill’s–clinking their beer glasses and high-fiving passersby. They credit their “superior design” for the victory–but can’t agree on whether they should modify their racer for the 2015 race.

Kristy Poore of the Ann Arbor Area Convention & Visitors Bureau says the Canadians have indeed registered for this year’s race, along with about a half-dozen other teams. Whitaker stands ready for the challenge: “We need to bring the trophy to the states!” He says his crew plans to add “better wheels” to their racer before the big day.

This year’s UA Block Party runs from 6 p.m. to 10 p.m. August 10. To check out the tricked-out toilets and to find out if any of the American teams can flush out the Canadian competition, report to Main St. by 7:30 p.m. The Big Flush immediately follows the 5 km race.