...here is the California Bluegrass Association site:

   CBA

Check out the "Huck Finn" in So. Calif., the "Kate Wolf" in Central Calif., the "Father's Day" in Northern Calif., and the "Strawberry" in the Sierra Nevada Mountains. The CBA sponsors the "Father's Day Festival" in Grass Valley each year. Of the four mentioned, it is the only truly "bluegrass" festival. The "Kate Wolf" gets a bit political but the line-up this year is awesome. Get tickets early.