Connecting with home school groups without Facebook?

Hi everyone,

I've read here that the East Bay home school group is pretty active and is organized primarily on Facebook. I have never had a Facebook account and would love to keep that streak going, so I'm hoping someone here might help me connect with them via email.

Our family moved to Berkeley last year. Our three children have all been home schooled (secular, STEM-focused), but the two eldest are now at university and our youngest son, who is ten, has become an only child in some ways. He plays chess at BCS and attends a robotics club, but these have not yielded any social opportunities outside the organized activities. I'm hoping to join some park days, but without Facebook, I've not found a way to join the home school group(s) or learn about activities.

I'm also interested in any other advice the community here might have to offer to help my son make friends. He's really into astronomy and cosmology, plays piano, loves reading, biking, and building stuff, and plays Kerbal Space Program, Universe Sandbox, and Minecraft.

Thank you,
El