I took up cycling. When I was 35 I was having trouble with back pain that I assumed was rooted in not exercising. I find cycling to be the least objectionable form of exercise. My hip popped back into socket after a couple weeks and that was the main cause of back pain but I find I feel significantly worse and am less productive if I don't keep up with the exercise.

For purely code stuff, I tend to learn a new language when I don't want to program anything. I particularly like ones with non-mainstream philosophies as they provide a different perspective on the craft. I don't do much with the languages I learn but it usually kicks me back into regular coding.