UC Berkeley Extension
In keeping with its populist ideals, Berkeley provides a variety of continuing education options. Extension courses are offered in many cities in the Bay Area, in addition to online courses and enrolling in regular courses without credit. They have quality teachers and programs, and fairly reasonable prices (though still much higher than the community colleges). You do not need to have a GRE, GED, diploma, or apply for admission in order to take a course. For the details see http://www.unex.berkeley.edu/