The Lean Startup Machine is a weekend-long startup competition that conforms to Lean Startup principles, a method of using customer feedback to rapidly iterate your product to reach product/market fit. http://theleanstartupmachine.com/
The Lean Startup Machine SF Meetup Group is an official extension of #LSMSF 2011, created in order to keep the energy going and to support a network of people in the Bay Area who are actively working on Lean Startup principles. We hold semi-regular gatherings to share learnings, network to find new partners, and just hang out.
#LSMSF Meetup is hosted by 8foldlabs, a Lean Startup Laboratory in the heart of SOMA. http://8foldlabs.com/