The Annenbergs' estate is set to open to the public: http://www.nytimes.com/2012/01/24/us/annenberg-estate-sunnylands-to-open-to-the-public.html
It might be a bit far for a meet-up, but I thought people might be interested. Also, there is a lesser-known Annenberg property that is open to the public and is rather neat--the Annenberg Community Beach House. http://beachhouse.smgov.net/
You can go hang out by a beautiful marble pool with chairs for a small fee.