Yoga
A collection of free online yoga classes for all levels
Online Yoga classes has been a lifesaver for me, both physically and mentally. I know some find yoga inaccessible, either because of cost or physical ability, but please know - you're never too inflexible to start. Just like you're never too old to start taking care of yourself.
Get yourself a yoga mat (I recommend Maduka) and start experimenting with yoga at home. Most of the yoga classes I share from Youtube are free, or you can invest in a 3-week progressive program that will teach you the basics as a beginner.
There's something here for everyone.