I recently started skateboarding again after many years. I've been going to the local skatepark at least twice a week at a time when most people don't go (early mornings). There, I've met a bunch of other dads reconnecting with skating (and probably their youth).

Before, I used to live in DC and was obsessed with golf. I'd go down to a nearby public golf course at first light. Often I'd join a foursome of total strangers, I've met all sorts, lawyers, a local news presenter and even someone relatively high up at NASA.

I realized that the theme for me was to simply pursue what you love, commit some time to it. This leads naturally to meeting people with a common interest.