For those who were lucky enough, it's the perfect day to play hooky.
The members of Poor Man's Whiskey know from experience. It's their eleventh year playing here, this time for a crowd of kids allowed to cut class.
Scores of school kids skipping class on this gorgeous day as their teachers bring them to Hardly Strictly Bluegrass. pic.twitter.com/hFLDb1GITL— Jonathan Bloom (@BloomTV) October 2, 2015
Hardly strictly music: Kids kicking off the weekend's bluegrass festival are getting treated to a circus performance. pic.twitter.com/fDli8aUcg9— Jonathan Bloom (@BloomTV) October 2, 2015
They're playing their bluegrass instruments but not the traditional tunes. They want to send kids a message. "With modern technology, cell phones and you know, people are so connected to their devices that we could show kids that you could pick up a guitar, a fiddle, a banjo, make some noise and get really a lot of joy out of it," one band member said.
It's the very joy philanthropist Warren Hellman wanted to spread when he started the festival.
"I think he kind of wanted to create this utopia and have the base of it be bluegrass music, cause that's such an American tradition," granddaughter Olivia Hellman said.
Back then, it was Strictly Bluegrass, now that's hardly the case. "And every year I see a band that I never would expect to see here that I really like," fan Brian Fritts said.
Fans like Fritts come back year after year and new ones are coming all the time.
Hardly Strictly Bluegrass opening acts have kids transfixed. Should we try to teach some algebra while they're here? pic.twitter.com/JETDqhkDHj— Jonathan Bloom (@BloomTV) October 2, 2015
One thing has never changed. "No selling anything, there's no products to be pushed. The only thing pushed is a good time and having fun," Olivia Hellman said.
That was Hellman's vision and his grandkids are proud that he left behind the money to keep it that way.
"It's been a huge gift to me and I think everybody that I know from the area just loves coming here. And it means a huge amount, I even know people who have moved to San Francisco because of going to the bluegrass festival," Hellman's granddaughter Avery Hellman said.
There will be seven stages with 100 performers. Headliners include the Indigo Girls, Los Lobos and Emmylou Harris. More than 750,000 people are expected at this weekend's festival.
The good thing about a free concert is that you can just show up to Hellman Hollow in Golden Gate Park any time between 11 a.m. and 7 p.m. and just walk right in.