Fun Track Dayz is loads of fun. They provide free transponders, free donuts and coffee in morning and free water all day long! They have an IOS app that tracks your laptimes so you don't have to worry about looking up timing sheets posted on some back wall some place.
Their remaining schedule for 2017.
May 29 - Thunderhill East
June 16 - Thunderhill East
August 14 - Thunderhill East
September 9 - Mazda Laguna Seca
September 16 - Thunderhill West
September 17 - Thunderhill West
October 9 - Thunderhill East
November 13 - - Thunderhill East