Do you want to challenge yourself mentally and physically? Have you spent too much time on Twitter and need to get out more? Are you simply an adrenaline junkie? If you can answer yes to any of these questions, then this is the group for you. Formed by and for those who love mountain biking. Whether you do it for fitness, for the rush, or to impress maw and paw, you'll get all of that, and then some! Weekly adventures all around the Bay Area. People of all skill levels are welcome. N …