The spiritual or meditative practice that keeps me feeling zen... is not actually spiritual or meditative at all I suppose. Whenever I am in need of de-stressing I take a drive. I take a drive down the back roads with my windows down. And generally I stop at lakes or rivers. I sometimes take pictures. It is the "alone" activity that really helps clear my head. And while it doesn't necessarily help me reach my inner soul... it certainly makes me feel a hell of a lot better. Plus I love adventures and they are kinda of mini-exploring-adventures to me.
I haven't been good on this zen stuff, but I feel that writing always helps me keep in touch with what's important. Reading does as well. Also, listening to music (habitually) helps, and biking has become a new thing that could also contribute to my zen. However, I haven't taken on any spiritual/meditative practices yet.