Updated

Hundreds of thousands of people took to the streets Sunday for Gay Pride parades (search), energized by the Supreme Court's ruling that struck down laws against sodomy and a decision by Canada to allow gay marriage.

In New York, Atlanta, Seattle, San Francisco and other cities, revelers marched, danced and carried banners congratulating the Supreme Court (search) for its landmark ruling as rainbow flag-waving crowds lined the streets.

"There's such a resonance, such a sense of movement," said Marty Downs, a community organizer with the New York Lesbian, Gay, Bisexual and Transgender Community Center (search). "This year, it feels really political."

Even before the ruling Thursday that struck down a Texas law banning sodomy, the committee that puts on San Francisco's massive parade, one of the best-attended events in the state, had decided to infuse this year's festivities with a more activist bent.

"We got a couple of breaks in the last few weeks, with Canada legalizing gay marriage and now the Supreme Court," said Supervisor Tom Ammiano, one of two candidates vying to become San Francisco's first gay mayor this year. "It looks like Sandra Day O'Connor watching Will & Grace really paid off."

Despite this year's historic backdrop, the events in cities around the country maintained their colorful, Carnaval-like atmosphere. They featured naked cyclists, fluffy pink boas and floats swaying with singing drag queens.

As in years past, the lesbian motorcycle group Dykes on Bikes got the San Francisco parade off to a roaring start with hundreds of leather-clad and topless women astride motorcycles.

"It's a big party," said Jeffrey Sykes, 37, who has attended at least 10 Gay Pride parades in San Francisco. "It's a chance to let it all hang out and celebrate who we are."

The parade's theme was "You Gotta Give Them Hope," a campaign slogan that belonged to San Francisco's first openly gay city supervisor, Harvey Milk, who was assassinated along with Mayor George Moscone 25 years ago this November.

The SF Pride Committee also used the occasion to encourage people to lobby the state Senate to vote for pending legislation that would grant gay couples most of the same legal and financial benefits as married heterosexuals. Police would give no crowd estimates.

As they basked in the Supreme Court decision, many participants said they looked forward to a new era of equality and respect.

"We're all together, one family," said Armando Gonzalez, 21, of Issaquah, Wash., who took part in Seattle's parade as a member of a youth choir made up of both gay and straight singers. "There are no barriers."

On June 10, an Ontario appeals court ruled as unconstitutional Canada's definition of marriage as only between a man and a woman -- paving the way for legalized gay unions there.

Then last week, the U.S. Supreme Court made its 6-3 decision that apparently swept away laws in a dozen states banning oral and anal sex for everyone, or for homosexuals in particular.

Both supporters and critics of the decision were quick to suggest it could lead to other legal advances for gays and lesbians -- including the right to gay marriage -- and organizers said a feeling of hope would carry over to the marches and celebrations this weekend.

Chicago's parade drew between 375,000 and 400,000 people, according to parade coordinator Richard Pfeiffer. Organizers of the Atlanta Pride Festival, now in its 33rd year, said they expected a crowd of 300,000, the largest in the parade's history. The ruling was cited as a factor in the big turnout.

"You couldn't ask for a better reason to come out and celebrate," said Philip Rafshoon, owner of Outwrite Bookstore in Atlanta's traditionally gay Midtown neighborhood. "A lot of people think [gay sex is] immoral. And, unfortunately for them, it's not illegal anymore."

One participant in the St. Louis PrideFest said this year's parade seemed more vibrant, more celebratory than previous years. She attributed the large crowd in part to the Supreme Court ruling, but that wasn't all.

"We're becoming more comfortable in our own skin," said Robin Hanson, 41, a doctoral candidate at Saint Louis University. "I've been 'out' for 20 years and there have been a lot of changes in acceptance since then."

St. Louis police had no crowd estimates, but organizers predicted as many as 15,000 to 50,000 would attend the weekend of activities.

Speaking through a megaphone at the New York parade, Sen. Charles Schumer, D-New York, took note of how much the political landscape for gays and lesbians had changed with a few short days.

"Let's hear it for gay pride," Schumer shouted. "Let's even hear it for the Supreme Court -- who ever thought we'd say that!"