If you want to get a lot of driving time (and who doesn't?), then the Porsche Owners Club (
::Porsche Owners Club::) is the place to go in SoCal.
I joined the Performance Driving Series (PDS) in Feb and will have done 9 track days in five months (after this weekend). PDS has 9 more events scheduled for the remainder of 2011 and a few other events where you can drive the same track as the Cup racers (in a separate PDS group) so there is lots of opportunity on a variety of tracks.
Great instructors are provided at no charge. Very affordable with tons of driving time. POC is a great group of people who are very friendly and quick to help in any way possible.
Website has good info (click on DE/PDS Info) or just drive up to SoW this weekend and check it (us) out.