Off the Grid's Roaming Food Truck Party and the Budget Gourmet Revolution

We've been buying cheap food off carts since the beginning of civilization, but over the past few years, there's been a quantum leap in the quality of the fare on the streets of many American cities. San Francisco, a city known for sophisticated palates and rigorous ethical standards, is home to Off the Grid, a flotilla of food trucks that roams the city, attracting musicians and crowds wherever it alights. I paid a visit to the event at Fort Mason, on San Francisco Bay, to see what the future of cheap street eats tastes like.