I’ll add dancing to this list. It’s certainly possible to just show up, do the steps, and leave, but it’s an atmosphere where talking to people is very easy.

If you go to a class for a few weeks/months, you’ll start hearing about other classes, or events. You also might end up finding that you have other connections with some people who you dance with.

I speak from experience here. I’m not very good at people, started dancing for that reason, and my time dancing has helped noticably, according to an old, long distance friend.