I love Weekend Sherpa, even though I'm not sure how I feel about its name, because doesn't "Sherpa" refer to an ethnic group, not the vocation of guiding trips? In any case, this website rocks - every Thursday it emails a list of outside-y things to do over the weekend in the Bay Area.
Its suggestions this week include a hike in wine country, a kayak trip in the largest estuary in the lower 48 states, a bike ride in "Little Tuscany", campgrounds still available in Yosemite (!), and the best place to BBQ on Treasure Island. I heart weekends - and sherpas, apparently.