As thousands of people flocked to this year's ninth annual Hardly Strictly Bluegrass festival in Golden Gate Park, most paid attention to the performers on the stage rather than the first aid medical tents around the parameter.

These tents are operated by volunteers who decide to work while they enjoy the music. "We are mostly run by donations," Karen Fabrizius, a volunteer EMT at one of those tents, said. "And so sometimes, it's making the best of what you have."

Hardly Strictly Bluegrass is a three-day free festival that showcases local, national and international musical talent. Beginning at 10:00 am and ending around 8:00 pm, festival goers enjoy a day of music with bands like Okkervil River and Earl Scruggs. And thanks to the help of volunteers who donate their time, like Fabrizius, the festival remains free of charge.

Rock Medicine is the non-profit organization that sets up these tents to serve as mini-emergency rooms so they can deal with injuries and other medical issues during concerts. All the EMTs and nurses who work in these tents are volunteers.

Wes Fifield, Director of Rock Medicine, started out as a volunteer himself 15 years ago. "I first heard about it in college and as soon as I did it, I was hooked," Fifield said. Now as the director, Fifield oversees 300 volunteers for over 600 concerts every year. A total of 30 volunteers from Rock Medicine alone worked this year's Hardly Strictly Bluegrass festival.

"There's something that runs in all these volunteers and that's the spirit of helping people," he said. "It's quite a payback, actually."

For Fabrizius, while the payback is great, times can be hard when resources are strained. "There aren't enough people who volunteer," she said. "And so it can be very hectic." Supplies are usually low. People who donate their time are scarce. And there are always patients to help.

Despite these setbacks, Fabrizius loves what she does. "I don't think you need to make lots of money to feel rewarded," she said. "Just, hopefully, more people will volunteer in the future."

But medical workers are not the only volunteers you can find at Hardly Strictly Bluegrass. Information booths are set up in some areas to assist any festival-goers with questions about line-up, merchandise, location of ATM machines and anything else they can think of.

Elliott Selzer has volunteered at one of these booths for three years. He first heard about volunteering when working at folk/rock radio station called KPIG. Now, Selzer likes giving back to this musical community while still getting to enjoy the atmosphere of the festival. "I love music," Selzer said. "I like a lot of the bands here, but it is also a great place to discover new bands as well."

While volunteers are the fuel that keep the Hardly Strictly Bluegrass engine running, they do not pay for the festival itself. That is the generosity of billionaire investment banker and bluegrass enthusiast Warren Hellman. What began as a modest music festival soon grew into a multi-stage affair, with guitar and banjo-toting musicians traveling from near and far to participate. And not all of them are known for bluegrass music. Steve Martin's band, The Steep Canyon Rangers, and MC Hammer were in this year's line-up.

As a thank you to Hellman, volunteers like Selzer put together a scrapbook for attendees to sign as a thank you for this gift to the city. Lyndsey Schlax waits in line with her father and sister to sign the book. "It's just so great that Warren and these volunteers would do this for us," she said. "This festival is a great part of San Francisco culture."