Back in 1969, the legendary Johnny Cash released an album that was recorded live at San Quentin, one of America's most infamous prisons.
Cash sang "San Quentin, you've been livin' hell to me" and for good reason.
Over the past 160 years, that prison has housed serial killers, child killers, and mass murderers including the notorious Charles Manson.
Not exactly a place where you'd expect to find entrepreneurs in the making. But these days, prisoners at San Quentin are learning the ins and outs of free enterprise.
They're taking part in the Last Mile Program which is designed to help prisoners deal with the most difficult, and often neglected, part of rehabilitation - their release back into society.
The idea is to help inmates develop business start-up ideas. It's offered twice a week over six months but as you'd expect, it's very low-tech. Cellphones and mobile devices are banned, and prisoners can only use a computer, if they're supervised.
As a result, the inmates - who are selected to take part - read books by digital media experts, attend technology seminars by outside experts, and get to speak with mentors from tech companies.
At times, there are high-profile guest speakers from Silicon Valley, such as Motorola advisor Guy Kawasaki and Quora web executive Marc Bodnick.
The founder of the Last Mile program is Chris Redlitz, a local venture capitalist. He told Reuters he never expected to find a real investment opportunity in a prison; he just wanted to educate inmates about the high tech business.
Overcrowded San Quentin - designed for 3,302 inmates and housing 5,247. It costs the state of California $184million a year to operate
Recently, they held a 'Demo Day' where seven prisoners presented startup proposals to investors and the media.
Eddie Griffin (not the Undercover Brother actor) was one of them. He's spent 15 years in prison for drug possession, but developed a music streaming concept called "At the Club".
"Live stream has gone mainstream. Mobile video usage went up and is expected to increase by 28 percent over the next five years," Griffin said in his pitch.
Griffin told Reuters: "I still have a lot to learn. I've never used a cellphone. Technology is kind of foreign in this environment."
Christopher Schumacher is serving 16 years to life for second degree murder. He sees the program as a chance to "learn about the world of technology and social media that is normally not offered to men in prison."
His idea, 'Fitness Monkey', is a mobile exercise app that helps substance abusers avoid relapsing, by reducing depression. The app includes a personal trainer that can be contacted through the app.
Jorge Heredia was a grocer before his sentence - 13 years to life for attempted murder.
His 'Funky Onion' venture aims to buy produce that doesn't look so great but is still edible from farmers, and sell it for a lower price to restaurants. He hopes to one day run his own business and help underprivileged youngsters.
San Quentin's death row
John Collison, 22, and the co-founder of online payments start-up 'Stripe', was in the audience and noted some stark differences between the inmates' proposals and the ones in Silicon Valley.
"What's frustrating is that all these companies in the Valley, they're ideas for the 1 or 10 percent...something to help you find a driver or find someone to clean your house. Are they solving real problems?"
The San Quentin inmates "were talking about urban obesity, or PTSD", said Collison. "It's a completely different perspective. We actually really need that."