Every year the weekend before Memorial Day there is a gathering of people from the MTBR Norcal Forum called May By the Bay. This year there were 6 rides, with the final three days rides at Annadel Park, Boggs Mountain, and Oathill Mine Trail. It’s an informal gathering with no official sponsors and it’s 100% free, even the camping at Boggs is free.
Fiona and I went to the Annadel ride on Saturday and rode at Boggs Demonstration Forest on Sunday and Monday. Both Boggs and Annadel are amazing mountain bike friendly parks with miles and miles of awesome trails. If you like fast buffed singletrack you can’t go wrong at either place. I’ve been riding at Boggs for 5 years and every year there are more and more trails there.