The Ventura Area Theatresports group has been around for a long time and is run by a very talented group of folks. They are part of the Theatresports franchise (Keith Johnstone's group), and I highly recommend their performances and their workshops. The same folks also operate the Livery Theatre and so you can check in at http://www.liverytheatre.org/ for the latest info. Currently, their open workshops are on Saturday morning and Monday evening, and their shows are generally on Friday and Saturday evenings.