I now hit the gym about three times a week (I always have at least one day off between workouts) for my abs and upper body. I'll never be Mr. Olympian but after about a year and a half, there's a little bit of muscle there! It's at the national fitness chain that has the $10/month basic membership.
I have gotten into several hiking groups, partly for the exercise, partly for the scenery, and partly to keep social skills up. Since I'm a widower, finding female companionship is a struggle (I'm just not into overweight seniors). I now wind up hiking more than biking, at least for now.
I also watch over my grandson a few times every week. Although sometimes it's a pain, overall that is good for me--gives me a chance to be of service to others, and also my daughter always sends leftovers home with me.