Riding through town for another year Friday, cyclists will once again pilot their zaniest two- (or more) wheeled creations as part of Stupid Bike Night, a fun, annual affront to all manner of convention where anything goes — as long as it can pedal.

Last year, the fleet included a toilet bike, a home music studio bike, a rickshaw with bicycle wheels for a canopy, and a sheet metal-clad rocket bike complete with an open flame jettisoning it into the night — a fan favorite. More than 40 riders in wild costumes took to their own bikes after dark, some decorated with lights, stuffed animals and other found odds and ends, and briefly shut down the road through town. Their creativity is elevated by the wish to make their bikes as absurd as possible while having a good time among friends.

“We want to build bikes that are so cool that they almost border on ridiculous,” said Kevin Kim-Murphy, a club member and organizer of the event. “As one guy put it, ‘We think physics are stupid.’”

The Stupid Bike Club, consisting of about 20 regular members, formed in time for the 2014 Strawberry Festival, when they considered ways to join the parade. They settled on the idea of riding truly unusual bikes among the floats and marchers, customized in a welder’s shop on Vashon’s west side, but according to Murphy, “Nobody in our group could get their act together to get that going.”

The bikes they imagined, however, were too good to pass up. In their spare time, they built more of them, each one stranger and better than the last. They chose the first Friday of September to let the bikes lose.

“It started as just [us saying], ‘Hey, we can finish off summer [this way] … but it became about building these silly bikes and creating a parade. It became a whole other thing,” said Murphy, adding that the original Stupid Bike Night was such a success that it became a tradition on the first Friday in September.

As in past years, the club has a barbecue, where donations are accepted to support additional “stupid” bike projects. Riders have usually started north of town and then proceeded to surround the four-way stop. They eventually migrate to island bars and restaurants, taking note of any “stupid” bike casualties along the way — on Saturday morning, Murphy loads any misbegotten wreck left behind the night before into a trailer to take home. He said that frequent bike breakdowns are common when the level of “stupid” is pushed far enough. The toilet bike, for example, is back after a poor show last year where it had to be pushed.

There will be a lot of bicycles on Vashon’s roads this weekend, “stupid” and otherwise. Athletes will face the Passport to Pain Saturday, riding up the island’s most challenging inclines. Generally speaking, said Murphy, the “stupid” bikes can’t climb hills or cross much terrain. But what they lack in agility, they certainly make up for in spirit.

“A lot of our stuff is found art. We find recyclable objects and turn them into artistic things,” said Murphy. “It’s funny how random people will show up and say, ‘Hey, can I ride a bike?’ and we say, ‘Yeah, here,’ and they just ride and have fun. That’s the whole thing. It’s not a show per-say, it’s more than that; it’s an interactive experience.”

One of the “stupid” bikes Murphy has most enjoyed watching each year is the rocket bike, designed by the island father-son duo Rob and Rex McFarlin. The rocket bike is retrofitted with something totally new every year; its most recognizable feature, a flamethrower, was added the second year.

“When we realized we could shoot flames out the side of our bike, we realized we could do anything,” said Murphy.

The club will host their staging area in the parking lot of the Chamber of Commerce, gathering there at 6:30 p.m. More information will be available online at facebook.com/stupidbikenight. They are expected to come through town about 8 p.m. Friday.