I may or may not have mentioned my daily walk, and how vital it is to my writing and my life in general.
On days when I go to my day job, I walk to and from the train station. On other days, I can manage a few miles.
I go rain or shine, wind or snow. (About the only weather that keeps me indoors is ice. I won't walk during a thunderstorm either, but those usually pass quickly.) I long ago learned that waiting for the perfect weather means rarely walking, so I take the weather as it comes.
It's a break in the day. It ensures I get out into the world and get some exercise and remind myself what season it is. It's meditative (if I'm alone) or social (if I'm walking with others).
Sometimes I consciously work on a story problem, or try to think up a title, or otherwise focus on writing. Sometimes I don't intentionally think about a story, but ideas will pop into my mind as I walk. Often I come home with a new scene or a new understanding of an existing scene.
Writers often sleep on story problems; many times I've heard that they wake up with great ideas. This doesn't really work for me, but walking does. Yet even without the bonus of the occasional story idea, I would still walk daily. It is, simply, nourishing.