Among them: Red Bicycle Breadworks, started by Brent Whitford and Brad Hart.
Hart set up a stand at the first market and then solicited products from area farms. He asked Whitford, then working at Chez Betty restaurtant, to provide bread.
"I made 16 loaves one day, brought them over on the trailer of my red bicycle, and the rest was kind of history," said Whitford, who moved to Park City from Connecticut a decade ago. "Sixteen became 40, became 80, and 100 and more and more. We decided we might have something here."
It became Whitford's full-time passion, and two years ago he began leasing space in the bakery at The Market grocery store. In addition to the Park Silly Market, Red Bicycle breads are sold at the Tuesday Pioneer Park Market in Salt Lake City and offered at a number of Park City restaurants.
On a typical Sunday, Red Bicycle sells 480 sticks of olive oil and Redman Salt bread its best-seller and up to 200 other specialty loaves featuring locally produced ingredients, such as spent hops from Wasatch Brewery and artisan cheese from Gold Creek Farms in Woodland.
"We spend a lot of extra time and money to get ingredients people don't really know about," Whitford said. "Being able to showcase what you're doing to such a large audience in a matter of a few hours and being able to market yourself face to face and explain exactly what you're doing is pretty exciting."
The Park Silly Market, which started with about 40 vendors, now has more than 160 booths; about half are operated by Utah natives a quarter from Park City itself. Last year, more than 132,000 people attended the market.
Entrepreneurs who figured they were on to something after stints at the market: Sammy's Bistro and Yee-Haw Pickle, said Ryan Cray, the market's media director.
Park City resident Kathy Pederson is another vendor who kick-started her business, Boom Dog Creations, at the Park Silly Market. About three years ago, Pederson, a retired special-education teacher from Las Vegas, found an old Western-style leather belt in her closet and fashioned it into a dog collar for Boomer, her yellow Labrador retriever. Her friends loved it and all wanted one, too.
She debuted at the market three years ago and now also sells handmade collars, wrist cuffs, bootlets and trophy dog bowls at the annual arts festival at Sundance and at the Cowboy Christmas show held in conjunction with the National Finals Rodeo in Las Vegas in December.
"I make it all myself so I'm busy," Pederson said as she custom-fit a collar for Monroe, a cocker spaniel. It was the third collar Orem resident Shea Wride has bought from Pederson.
"They always make our dog look prettier than she really is," Wride said.
Park Silly Sunday Market
The Park Silly Sunday Market takes place from 10 a.m. to 5 p.m. on Historic Main Street in Park City. It runs through Sept. 22.