https://groups.google.com/forum/#!forum/SFredditors & http://www.reddit.com/r/bayarea is pretty friendly, check it out! There is also http://sf.funcheap.com/ . There are also singular startup & tech industry events and such that pop up all the time in SF. Usually although I find those through friends since I'm not actively looking, there is probably some directory website having it. Most of them seem to be scheduled through eventbrite, so you can just look at the eventbrite directory here: https://www.eventbrite.com/directory