Sadly, I can't remember the last time I was on a seesaw, but
Seesaw cafe in Hayes Valley offered almost as much fun (and some Four Barrel coffee). I've walked by this place a few times now, and decided to bop in yesterday. The decor is something Alvar Aalto would love, and its concept is pretty cool: kids play space and cafe that also does workshops and private events.
My girlfriend and I loved the chocolate chip cookie and lavender/sea salt shortbread. Also, the owner is really nice and loves kids. It sounds like they're going to have some music or art events (beers, anyone?) in the evening, so it's fun even if you don't have any rugrats.
Oh, here's some photos, too: