CHURCH, CHURCH, CHURCH. There's none of the financial worries, pecking orders, or time constraints of workplace friendships, plus more of the freedom. You do it, supposedly, once a week, or more. There's no pressure to make small talk because you're there for another purpose as well, so if you get uncomfortable, you can just leave. As you get more involved, you start joining committees, planning events, coaching team…
I think the main problem is that we live in an increasingly secular society, but nothing has actually replaced church. And the people who are still at church, at least at many churches, are right-wing nutjobs.
I've also read about left-wing Catholics and Baptists (two cases where the main organization is generally seen as right-wing, but there are significant left-wing groups within them). I'm not a church-goer myself, so I don't have any suggestions on how to find a church you're comfortable with.