well, the SCA is in most big cities - so you can just google it and see. :)

I fell into it by accident. But there are lots of them out there. You just have to follow your own interests. There are often tight-knit communities that are built of fans of some obsession... that then just go on to build a community of friends - though not necessarily with the inbuilt morality function, but I don't think that's necessary... after all, you could instill a "pay it forward" mentality into any group.

I'm mainly familiar with the geeky and nerdy ones - SF fandom is another good example. But there are communities of expats, people dealing with certain life-issues (eg traditional self-help groups, weight-loss groups, single-parents groups etc), but also entrepreneurs clubs, alumni of various schools... basically whatever you can think up, some group has built a supportive community around it.

The SCA is unusual only in that it really attempts to build a long-term community out of what people would normally consider to be a short-term interest. I've known third-generation SCA members (ie their grandparents joined and their children and grand-children grew up in the society).

...and if you really can't find a group like that nearby... you can always start one.