Richie Havens was supposed to perform only 25 minutes at Woodstock in 1969.

Three hours and a remarkable moment later, he walked off the stage in that muddy upstate New York field with a place in pop history and a crowd of thousands chanting, "Freedom!"

"It was the biggest happening in the world," Havens recalled of that weekend and that moment. "It was people, young people, trying to get together with older generations."

This weekend, Havens will re-create some of that magic and energy when he headlines the 18th annual Tucson Folk Festival. He'll share the limelight with 70 local and regional acts on four Downtown stages all day Saturday and Sunday.

It's the Tucson Kitchen Musicians' Association's annual shindig to promote live acoustic music. Highlights this year include teaming up with El Centro Cultural's Tamal Fiesta to add a Cinco de Mayo celebration.

Havens performs at 9 p.m. Saturday and 8 p.m. Sunday at the Plaza Stage in El Presidio Park.

"The interesting thing is they're still letting me do this," the 63-year-old grandfather of five said last week from home in New York City.

Havens got his musical start playing doo-wop with a few buddies on street corners in his native Brooklyn. He wrote the songs, choreographed the dance moves and sang baritone, never imagining that he would one day step out of the shadows as a singer.

When he wandered into Greenwich Village - "the shedding place for artists, young people who run away from home and want to do something big" - he heard a different song.

"It was the songs that I heard that changed my life. The songs made me pick up the guitar," he recalls.

Armed vaguely with the knowledge of how to tune his guitar, he spent three days learning five songs before his first solo gig.

He was such a smash success that he spent almost seven years at the club. When he finished his sets there, he club-hopped around the Village, doing as many as 14 sets a night.

"It was completely magic," Havens said, unable to hide the giddiness that creeps up when he recalls those days. "There were so many good people to listen to and so many clear lyrics about where we were in that point in time in our nation, in our world, in our hearts and minds."

Havens has recorded more than 20 albums in his four-decade career, his last one, "Wishing Well," in 2000. Later this month, he will go into the studio to record a new album of songs that explore the latest political climate and world events that make Havens long even more for the turbulent yet settling '60s.

This weekend's festival will cover the musical gamut from Celtic and Cajun to traditional folk, blues, bluegrass and gospel. Artists include Tucson faves The Mollys, Four Corners, The Wayback Machine, Kathleen Williamson, Black Leather Zydeco, Catacoustic Groove, Trim the Velvet, the Titan Valley Warheads and the Balalaika Orchestra.

In addition to performances, the festival will include various instrument and songwriting workshops and events for kids.

El Presidio Park is bordered by West Alameda and West Pennington streets, west of Church Avenue. Workshops and interactive events will be held west of City Hall and at Old Town Artisans.