Personally, I hate the gym. It's boring, I don't look forward to it and don't go. I did, however, join Curves a number of years ago and went a couple years until back surgery. After I healed and went back to Curves, I realized that those machines were what was causing me back problems so I stopped going.
I walk (usually 4 miles) in the warmer weather. In the winter months I curl (that winter sport on ice). I curl 3 times a week competitively (6 hours of very good exercise) plus I practice one hour (or more) a week throwing stones. In a two hour game, I run/walk and vigorously sweep about 2 miles. It's great aerobic exercise, but also good conditioning for the legs, butt, arms, shoulders and back. Don't need to go to the gym and lift weights (thank godness). I didn't start out doing all this. Three years ago I curled one night a week and I've worked up to this. Repetitive motion, injury and I go way back, so I always need to be careful. Wish I liked to ride a bike, but I don't.
I'm almost sorry when the warmer weather hits and curling ends. I've been in a summer croquet league now for 17 years, but....no exercise there unless you count the elbow!