And here are some events I recommend checking out:

http://www.hackersandfounders.com/

http://www.meetup.com/106miles/

http://sanfrancisco.designersandgeeks.com/

http://superhappydevhouse.org/w/page/16345504/FrontPage

http://sfnewtech.com/

http://svnewtech.com (self-plug)

http://wiki.hackerdojo.com/w/page/40276058/Happy Hour

http://startupdigest.com/silicon-valley/

but you may want to consider couchsurfing for 2 nights up in San Fran.

Some ideas for SF:

• Drive to the top of twin peaks - alternatively walk from 24th St BART to the Bernal Heights hill (as you'll need a friend in a car for twin peaks, but Bernal is easier to get to, not as high, but still a good view)

• Visit SF's China Town, not as authentic's as singapore, but still pretty hopping.

• If there's anybody you're meeting for lunch in downtown SF, suggest South Park where lots of geeks go

• Head to a farmers market on Saturday mornings at the Ferry Building

• Stroll down Valencia Street btwn 16th & 24th St and poke your head into random shops, like Paxton's Gate on Valencia, btwn 19th & 20th.

• Grab a burrito at El Farilto on Mission & 24th, the most fun is after a night of drinking around 16th & Valencia

• Walk around Fishermans Warf - it's uber touristy, but with checking out and smelling some fresh Boudin Bread

• walk down Haight St, and cross Ashbury St where the whole drug/hippie scene started in the 1960s - they used to give out LSD for free on that corner!

• Check out the golden gate bridge, maybe rent a bike and ride around the east and north coasts of the city, to the bridge.