Music festival season is just around the corner. As the big ones begin to announce their lineups, turn your phone off for a night or two and head out for a warm up: San Francisco’s Bluegrass & Old-Time Festival kicks off on February 7. In its 13th year, the non-profit SFBOT (I wish I could take credit for that acronym) boasts a handful of shows at 18 different venues over the course of 10 days.