There were the electric cars, the climbing wall, the sustainable village and all the other things that Democrats like to show off on display at CarolinaFest, the street festival that kicked off the Democratic National Convention here Monday.

And then there was the real purpose of the event, at least for President Obama’s campaign.

“You want a free bumper sticker?” a young Obama worker shouted to people passing the president’s campaign booth, standing three feet above them like a 21st-century carnival barker. “Text 62262 and you can have one. Did you do it? Perfect! Here you go.”

In the space of a few hours, organizers had passed out hundreds of bumper stickers, collecting just as many cellphone numbers and — they hope — new recruits who could help replicate the grass-roots force that grew out of the convention in Denver four years ago. Others trolled the crowd, estimated at 30,000, with clipboards looking for would-be voters to register. And volunteers asked for signatures to support women’s initiatives and Obama’s health-care law.

“There are a lot of volunteers passing by,” said Samantha Steiner, 27, a Charlotte resident and registered independent who is not sure who she will vote for in November. “I don’t necessarily identify with the Democratic Party, but the festival has allowed me to find ways to participate.”

CarolinaFest was meant to be many things for the Democratic Party. It was a classic Labor Day street party, with water-ice stands, funnel cakes and bouncy slides. It was a public-relations parade intended to portray Democrats as inclusive (it was free and open to the public), compassionate (it featured dozens of good-works demonstrations) and fun (who doesn’t like a climbing wall?).

The festival was interrupted twice during the day by short-lived but torrential downpours, and it was cut short by the threat of severe weather. James Taylor, the headline performer, was singing when organizers called it a night in the early evening.

In some cases, the politics and the party were an odd mix.

At one end of the festival, White House Communications Director Dan Pfeiffer was spotted walking down the street in a suit and button-down shirt, taking in the scene.

At the other end, organizers with the North Carolina AFL-CIO beckoned passers-by with a provocative offer: “Free hugs from union thugs!”

“You ready for a hug?” Lora Banner, a Teamsters member and United Parcel Service worker from nearby Gaston County in a blond up-do, asked one man who had strayed closer to the tent. “Come on over here!” She put her arms around him.

Irritated that the Democrats chose to hold their convention in North Carolina, considered a non-union-friendly state, many labor groups scaled back or yanked their financial support for the event. The state AFL-CIO, however, opted to reach out for the folks on the street. By 4 p.m., a team of volunteers including schoolteachers, firefighters and other card-carrying union members estimated they had doled out about 400 hugs — and handed out cards showing how huggees could find a photo of their embrace on the organization’s Web site.

“We thought it was a good way to show that union members are not scary people,” said MaryBe McMillan, secretary treasurer of the state group.

Even one of the centerpiece debates of the election campaign played out as street festival fare.

Gagandeep Mangat, a radiologist from St. Petersburg, Fla., stood beside an RV belonging to Patients Over Politics, an initiative led by physicians in support of the Obama health-care law.

“We are a group of physicians who want to make sure that people understand why it is important that we have this law,” he said.

As he tried to explain, he was interrupted by a California woman who wanted to know whether he supported adding a “holistic medicine component” to the law. Mangat emphasized the importance of simply preserving the law. “If we have the law then we could add anything to it,” he said.

Though the group is officially non-partisan, the doctors, who drove the RV from the Republican convention in Tampa to Charlotte, are also embarked on a voter registration effort they hope will help preserve the law.

“This started because as doctors we were so frustrated that our health-care system was not working for the patients,” said one of the group’s founders, Alice Chen, an internist from Los Angeles, “and the only people talking about it were either policy people or politicians.”

Even the most lighthearted features of the festival carried a political, or at least cultural, message: A “Peace In, Peace Out” yoga booth. A “Youth Soccer for Social Change” game underway in a parking lot. “Naturals for Obama,” a support group of black women who don’t straighten their hair.

Looming over all of that was a message from the Charlotte Diocese — a banner across the exterior wall of St. Peter’s Catholic Church reading: “Protect the Unborn, defend marriage, safeguard religious liberty.”

Amy Argetsinger, Ann Gerhart and Ed O’Keefe contributed to this report.