Tai Chi

Highly recommended, made this winter less bad, probably on account of moving the body around more, which might otherwise be too occupied fiddling with a computer (writing a bad fugue at the usual glacial pace, adding at-rest encryption to the bespoke e-mail workflow, reading about selfish genes, etc). Tai chi seems easier to maintain than more robust exercise or stretching, and can be scaled up or down depending on ability, mobility, and how much time is available. Also you can start slow and then get bendier as the tendons get used to things. And with restricted forms you do not need to even move around much, handy if you're in a room and the power is off, as may happen during winters in locations where power lines are strung below tree branches.