Once a year, San Francisco’s Golden Gate Park fills with the music of some of the best-known bluegrass, folk, and alternative country acts around. For three straight days, the likes of Okkervil River, the Old 97s, Earl Scruggs, EmmyLou Harris, Neko Case, and the Drive-by Truckers fill stages in the park’s northern meadows for the annual Hardly Strictly Bluegrass Concert. Best of all, you get to see it for free. So grab some friends, a blanket, and a picnic and head over to Golden Gate Park this weekend to enjoy great music and a gorgeous fall day.