Great idea. Here is something that could be similar but more niche (sorry if too niche): join a meetup group for that does indoor rock climbing. If, say, meetup is a big thing where you are. Otherwise, check for, e.g. facebook groups that partner up climbers -- meet and learn! (likely need to take a class to learn the very basics first, assuming you know absolutely nobody and there is no meetup for it.)
More laid back: join a weekly bikes-with-lights social biking group. Weekly trivia, meetups at bars for tech people, new people to the area, karaoke, etc. Play to your strengths/likes. Run and hit the gym to boost social confidence (now I am back at crossfit ;). Learn how to dress up just slightly more than standard for any occasion (non exercise that is) if you don't already know.
It's easier to make friends outside of work if you build some structure or drive into your life beyond work. Become interesting by having interests. Whatever you choose to do, keep doing it and eventually you will meet like minded souls.
I wonder where OP is. Location might have a say in what's popular and help find a matching interest.