CAMBRIDGE — Jason Targoff was coaching his son, Lou, in third-grade recreational soccer. The season was about to start, but no one had picked teams.

Targoff suggested an ad-hoc, World Cup-style tournament. Judging by his son’s reaction – “We get to fight Italy!” he beamed – Targoff figured the idea might be a hit.

Thirteen years later, that tournament of six teams in colored T-shirts has become a two-day soccer festival held every June, with Danehy Park stuffed to the gills with cheering parents and players wearing 24 countries worth of bright, bold imitation international jerseys.

That annual bash is the biggest community-building event for Cambridge Youth Soccer, which has an inclusive philosophy that has the attention of thought leaders in the youth sports world.

Here, fun-seeking casuals and fierce competitors alike play on the same teams. No one has to worry about getting left behind if they didn’t make the travel squad or because their parents can’t afford it. No family packs its SUV for an hour’s drive to a single practice. They walk, scoot, and bike their way to the soccer capital of the People’s Republic of Cambridge.

They believe in a low-cost, low-stress, high-engagement way of growing the game.

Everyone in Cambridge plays in a city league on Saturdays, with an emphasis on mixing abilities and ages. The games are eight-on-eight, with four cross-field games at once on a full-length pitch. Advanced players can join the Sunday club team that practices once during the week and plays in the New England Club Soccer League.

“But it’s all one program,” Targoff said. “The focus is the same. The philosophy is the same. More time on the field, less time in the car. Hanging out with friends, having the ball at your foot a little more often — all these things are really important.”

According to the Aspen Institute, the average American family spends nearly $1,500 a year on youth sports, and parents can easily drop tens of thousands to keep their spots on elite club teams. In Cambridge, fall and spring rec soccer costs less than $200 combined, and those on the club squad pay another $250.

Those fees are waived for anyone who can’t pay. Targoff said about a third of nearly 2,500 registrants are playing for free, “and we don’t ask any questions. We don’t have the bandwidth for that.”

They solicit donations to balance the budget. Those without equipment can use a lending library of hand-me-down cleats and shin guards. The city donates the use of its fields.

The program is volunteer-driven, other than a few paid staffers — including coaching director Alvaro Amaral and technical director Mario Prata, who oversee player development and about 200 volunteer coaches, who are mainly parents. Older players in the program, and high schoolers, earn a few bucks for refereeing games and teaching kindergarteners the basics.

Having pros help out is vital, Targoff said, so families don’t see rec soccer as a developmental dead end.

On Saturdays at Danehy Park, hundreds of players in grades 3 through 8 compete against each other. The teams contain highly skilled players, total newbies, and everyone in between. They wear the names of two dozen countries, from Eritrea and Ethiopia to Argentina and Brazil.

“They get really into it,” said Haining Gouinlock, as her third-grade son, Freddy, was warming up for Spain’s game against Portugal on a Saturday in mid-October. Her husband, Tom, was coaching in a retro Team Spain jacket she bought in her native Toronto.

“[The kids] think because they’re on Spain, they’re the best,” Gouinlock said, smiling. “They say, ‘We’re playing Canada, they’re going to be terrible.’ Well, the Canada team is a selection of Cambridge third-graders, just like you.”

They walk to the games, where Freddy has made friends from all across the city, at different elementary schools, and has reunited with pals from his old daycare.

“He’s happy,” his mom said. “Be on a team, get a little exercise, make friends. … I have no intention of doing cutthroat youth sports. I think this is wonderful.”

Last year’s World Cup tournament in mid-June consisted of about 1,250 players on 88 boys and girls’ teams. Bakery treats and $2 pizza slices flew out of vendor carts. Parents showed up with beach chairs and tents, watching their kids in 30-minute games. Tied games were not decided by pressure-packed penalty kicks; they just removed players from the pitch until someone scored.

“I think that’s lost a lot from our kids’ lives here in America,” Targoff said. “Like, they don’t have to be soccer players; they can play soccer. We can go out there and have fun. The irony is that we’re getting better, even though it wasn’t really our goal to make great soccer players.”

An eclectic place such as Cambridge is ripe for this kind of experiment. It has more than 120,000 residents, the fourth-largest city in Massachusetts. Some 30 percent are foreign-born. It has both a high level of affluence and a poverty rate on par with the state’s other urban centers. It is also walkable, bikeable, anything but car-dependent.

When he played in the league, Winslow Lively, a junior goalkeeper at Cambridge Rindge & Latin, would bike from his home in Cambridgeport.

“It’s such a good way to see your friends outside of school, and you don’t have to plan it,” Lively said. “Everyone’s like, ‘I’m gonna see you on the weekend and we’ll hang out and get food after.’ ”

Danehy Park was where he found his passion for soccer. He joined the league in the fifth grade, and still remembers the toe-poke goal that beat him in that year’s championship. His team won it all in eighth grade.

Those players are now part of a high school boys’ team that went from an afterthought, hardly competitive with powerhouse suburban schools, to the quarterfinals of last year’s Division 1 state tournament. The Falcons (8-1-3) were 10th in the Globe’s most recent rankings.

Their feeder system is more formidable than ever.

“We have 100 freshmen some years,” Lively said. “We have tons and tons of kids that try out, and the average level is really good.

“And seeing it here, the level has gone up since I played. It was a lot more of, give it to your best players and let them take it. But now it’s kind of everyone together.”

Matt Porter can be reached at matthew.porter@globe.com. Follow him on BlueSky at mattyports.bsky.social.