San Francisco OysterFest — the largest festival of its kind on the West Coast — returns for its 18th year to prove that oysters are the perfect accompaniment for just about anything. Electronic alt-rockers Passion Pit will be headlining this outdoor concert event at Sharon Meadow in Golden Gate Park that also includes Kongos (“Come With Me Now”), Sir Sly (“High”), Panic is Perfect and The Soft White Sixties.