By Julia Scott

IT'S THURSDAY NIGHT on the corner of 16th and Mission. James Marchetti delivers rhymes over the staccato beat of a snare drum, surrounded by poets, musicians, and misfits of all descriptions. His poem is an anthem for this group, and they know it well. Raising beer-swaddled bags in a toast, they shout it together: "Unafraid to listen! Unafraid to see! Unfraid to understand! Unafraid to speak!"

The 16th Street BART plaza can look like the opening scene of a crime novel. But every Thursday a group calling itself the Collaborative Arts Insurgency takes back the space for a raucous revival of street poetry. The group clusters in a semicircle that widens as curious commuters stop to listen. Standing on the corner with strangers amid the night noises of police sirens and honking cars, the feeling can be oddly intimate. On cold nights the crowd presses in for warmth.

Without a microphone, the participants have to raise their voices. When Mark Gurarie performed his first poem, he was so shy the crowd could hardly hear him. A friend would encourage Gurarie by standing 50 feet away, hand cupped behind an ear. Now Gurarie throws his voice across the plaza, raking the air with his arms. "This isn't a coffeehouse," he says. "People listen hard."

Many of those who find their way to 16th and Mission Streets have outgrown the city's coffeehouse poetry culture, with its comparatively tentative atmosphere and staid surroundings. On the corner, poets have their own backup band – drums, stand-up bass, and additional instrumentation. Couples have been spotted grinding out a salsa in front of the drum kit.

"Inside, you have to be polite, and that's not what it's about," says 33-year-old Miguel Pereira, one of the CAI's ringleaders. Pereira came to San Francisco in 1993 after obtaining a poetry degree from Princeton University, looking for the underground legacy of Allen Ginsberg, one of his favorite poets.

Not long after, he met Marchetti, Charlie Getter, and Keith Savage at a Wednesday-night Brainwash café poetry reading hosted by beat legend and community activist Diamond Dave Whitaker. Together they organized benefits, brought in live music, and published a poetry collection, The Common Thread. After a year and a half, they got tired of competing with people's dinner conversations. As the event became more popular, they moved on to another open mic at a Mission District café, but it closed, and they found themselves with no place to go.

They first performed at the 24th Street BART station in June 2003 at the suggestion of Shahid Buttar, who went on to found the Washington, D.C., Guerrilla Poetry Insurgency, a group that performs near the Dupont Circle Metro stop. "The first time was incredibly liberating," Pereira says. "There were no expectations because we weren't even supposed to be there."

They never miss a week; the event takes place rain or shine. The only rule is that no one can perform for money. It's a democratic venue – no featured performers or a sign-up list. Anyone can jump in at any point, including the seven-year-old boy who stopped by with his parents one night and belted out some Spanish songs.

Nicollee Nazemi discovered the group on her way to the bus stop. She was moved to recite a poem on the spot. "I've never seen anything like this," she says. The 25-year-old Los Angeles native stopped going to poetry slams back home because of a culture of "mini-celebrities." "There was always a leader and a bit of ego. Here, there is no leader," she says with a smile.

Except to answer the occasional noise complaint, the police stay out of the way. "When we're here, no one's selling crack or cocaine. I think they appreciate it," says Charlie Getter, who got into spoken word one day after reciting a poem out his bedroom window to a neighbor.

Spoken word, needless to say, has some history in San Francisco. The beats pulled poetry out of an insular realm; more recently, the commercial success of slam poetry has added a competitive edge to spoken word. But Getter warns against any attempt to classify the poets on the corner, whose performance styles vary as widely as their subject matter.

Their backgrounds differ too. Savage, a longtime member of the group, has been living on the street for more than 30 years. He grew up in Queens, N.Y., where he founded a traveling poetry group called the Black Poets, modeled after the Last Poets, the Harlem collective whose in-your-face rhymes put them on the charts in 1970 and paved the way for early rap. His poems are graceful, freewheeling trains of thought, as if plucked from the atmosphere. "The stuff we do at 16th and Mission I consider a lot hipper than the beat poets," he says.

The CAI poets know they're part of something new and compelling – as many as 60 people crowd the corner on some nights – but they don't have a mission statement. "It's an experiment we're all involved in. No one knows what's going on, but something sure is," says 22-year-old Sasha Khrebtukova, who performs her work with a Cookie Monster growl.

The CAI operates from the belief that poetry creates social change when it directly touches people's lives. For Pereira, that's a major part of the pleasure of being outside. "In this country, we're trained not to listen," he says. "So anytime anyone stops to listen, we've [knocked] them out of their rut."

Pereira and his friends have pulled stunts like surrounding a trolley car in Union Square and unleashing poems on surprised tourists. They make booklets of their words to give away. They perform in other outdoor settings, such as Kerouac Alley, but this Friday they're putting on a rare indoor show at the OmniCircus, using that intimate venue to explore a different side of their work. "Now people [can] get what they expected to find in San Francisco," Pereira says. "They say they came out to find the art scene, and they found it here, with us."

'The CAI Presents: The Get Down' takes place Fri/3, 8:30 p.m., OmniCircus, 550 Natoma, S.F. $5-$10. (415) 701-0686, www.omnicircus.com. The CAI also performs Thursdays, 9:30 p.m.-midnight, 16th Street BART plaza, 16th and Mission Sts., S.F.