I've tried a number of things over the years. Sailing, climbing, running, board game meet ups, drinking meetups, golf, crossfit, curling, probably some others I'm not thinking of. Just pick something and see if it sounds interesting to you and give it a go. My big advice is to avoid shelling out on gear. Rent or just get some beginner stuff. Most of these things didn't stick, but I'm a runner and a climber and oddly I've had some great platonic connections through crossfit as well.