Bay seniors looking for a snug, comfy, quiet bookstore with an extensive selection of rare and used books are encouraged to visit the clubby Book Bay at Fort Mason, run by the Friends of the Library. There’s a modest café next store with snacks and Blue Bottle Coffee. This Saturday bibliomania breaks loose in the nearby Festival Pavilion for the Friends annual Big Book Sale. “Big” is a misnomer. Half a million books, DVDs and books on tape are available in over 60 categories all for $1-3. Open 10-6. They expect to raise $500 million for the SF Public Library. Sign up to volunteer and for every 2 hour shift you work you are entitled to $5 worth of free items.