How about hiking to the top of Mt. Livermore on Angel Island for amazing 360-degree views of San Francisco, East Bay, Marine, Alcatraz, Golden Gate Bridge, Oakland Bridge, and more? See what others are saying about Angel Island on yelp: http://www.yelp.com/biz/angel-island-state-park-tiburon
If you're interested, join me on coming Wednesday at 10 A.M. at Pier 41 in San Francisco.
I plan to climb to the top of Mt. Livermore–it's a 5-mile loop hike (http://www.bahiker.com/northbayhikes/angelisland.html).
Angel Island is accessible via ferry (Blue and Gold Fleet: http://www.angelisland.com/Documents/Blue_Gold_Schedule_Oct29_May12.pdf). The ferry leaves at 10:10 A.M. and the round-trip ticket costs $17. We'll be back in San Francisco by 3:30 P.M.
Don't forget to bring water and some food!