The SF PHP Meetup (http://sfphp.org) is an open forum where PHP developers of all skill levels can come to communicate, learn, network, or just have a good time. We meet on a monthly basis and generally have speaker from the major web site companies in the bay area. Lively discussions or Q&A for hours afterward.
Our focus is in the PHP world but our topics encompass the entire LAMP stack. Topics include PHP coding, to memcached handling, db optimizations, server stack, web server tuning, code deploying, hosting options and much much more.