For me, I've recently taken up running. I have a full time job and a wife and three kids so time to myself where I can chill is rare. Running gives me an excuse to literally run away from it all and I can vary the length of my run depending on how much I need to destress. Bonus is that I also sleep better as a result of the extra exercise and I'm losing some of that middle age weight I've gained from sitting at my ass at a desk all the time.