Every Friday we put together a list of the weekend events we think look most interesting and provide them here. Keep in mind there is always a lot more going on, and all it takes is a little digging to find something that will be the perfect activity for you. Click on any of the event titles for a link to the event. Friday, April 1 6th Annual Spring Book Sale Fort Mason, San Francisco All Weekend, All Ages Free Hundreds of thousands of book & media for only $3 or less! Procee