The San Francisco Amateur Astronomers (SFAA) club has an open monthly meeting, where anyone may attend to hear very topical lectures on a variety of subjects related to astronomy and space research. The upcoming lecture and calendar are found on the website. And on Saturday February 16th the SFAA is hosting a Star Party and New Scope Forum where you can dust off and bring out your old telescope for a primer on how to use it, and then a chance to put it to work looking into the heavens.
The Peninsula Astronomical Society and the always-excellent Dr. Andrew Fraknoi put on star parties and outstanding lectures in Los Altos Hills. And the wonderful Chabot Space & Science Center has very fine telescope nights featuring their giant telescopes on Friday and Saturday nights year-round.
Get involved! You won't be sorry.