I recommend a gym, specifically a class based one like a boot camp or CrossFit. These tend to have a similar cohort of people who show up at the same time every

I recommend a gym, specifically a class based one like a boot camp or CrossFit. These tend to have a similar cohort of people who show up at the same time every week, so you’ll get an hour of exercise and social time wrapped up into one package. Friendship is created by repeated interaction. Anything that has you running into the same people repeatedly will typically create friendships.