Suze,
I lived in So Calif when I organized the first one. I was coming up for a visit to my sister in Sacramento and somehow it came together...with the help of several folks in the area. Then, I began taking care of my mom and couldn't make the trip up.
All it takes is a few people in Nor Cal want to get together and pick a location and a date. Where do you live, Fred? Anyone else in the Bay/Sacto area interested in sampling each others' tomatoes this summer?