The Collective, or Hero City as some call it, is your best bet in San Mateo. If you haven't seen it you should stop by, 55 3rd ave. Boost.vc rents space in the building for their accelector. I actually work in the Collective so I know firsthand that it's a great place to work. It's grand opening is October 10th.
Here is the Facebook page for Hero City, https://www.facebook.com/DraperHeroCity