The Anchor Brewing Co. tour is a great free activity. On the 90-minute tour of the company's Portrero Hill location, you will learn about brewing methods and the company's history. Guests may also sample beer at the conclusion of the tour. Kids are welcome. You must book the tour in advance.
Almost every weekend, there's a festival going on somewhere in San Francisco. There are free outdoor concerts at the Stern Grove Festival. If you are a Bard lover, look for the Shakespeare Festival. The North Beach Festival also is quite popular- and don't forget the street fairs. The street fairs in the Castro and Haight-Ashbury are legendary and you can enjoy both without spending a penny.
San Francisco's literary scene is not to be missed. It is easier than most any other place in the country to see famous authors in person at independent bookstores like City Lights and Book Passage. The appearances and book-signings usually are free. For a calendar of local literary events, go to www.kemblescott.com.
The Cal Sailing Club offers free sailboat rides every Sunday afternoon. The rides are on a first-come, first-serve basis, so don't wait until the last minute. You also can get all-you-can-eat barbecue at the end of the day, which also is free, although a $5 donation is suggested.