There was a young girl from Decatur
Who went to sing in the Thee-ate-er
The poor little thing
She started to sing
And they threw her a rotten Tom-ate-er
Well, that had nothing to do with anything now, did it?
But chances are I'm already too late for your visit. But you know, if you couldn't find modern things to do in San Francisco using your search engine, then you need to use a better search engine. Poor Richard's Search Engine might have been the best they had in the day, but times have changed.
And also search Lotta Living because there are plenty of hits on San Francisco, including this one with some suggestions just a few threads down on this page:
Have a great time!