Going for a walk
My family has always been about walking. My grandparents on my Dad's side took walks everyday and my grandfather on my mother's side enjoyed the same in the woods. Naturally, I followed suit.
On Sundays, I used to walk around a close by park with one of my girlfriends to catch up on the week and whenever I am going somewhere that isn't too far to, I walk. It's why I like living in the city, so I can walk everywhere.
It's a warm-up and preparation on my way, and a wind down on my way back. It's simply the most grounding exercise I know. And it provides me with space between appointments and home. Do you usually drive or bike? Try walking next time!