I personally find bodyweight fitness (aka calisthenics) incredibly challenging and satisfying. Good routines are based on progression from easier forms to more

I personally find bodyweight fitness (aka calisthenics) incredibly challenging and satisfying. Good routines are based on progression from easier forms to more difficult forms, emphasis on form over quantity, and at the end of the day, you'll learn some very impressive skills that require tremendous, functional strength. Equipment is minimal - a bar to hang from, a floor to resist you. There is enough complexity, challenge, and progression to last a lifetime. I gave up climbing for it. Reddit's bodyweightfitness subreddit is excellent. Head there for more info. The community's recommended routine is a perfect place to begin.