It helps me to get out and exercise--preferably far away from my computer (with which I obsessively check my checking, savings, and retirement accounts, fiddle with my loan payoff spreadsheet, and look at what the Dow is doing!).
Quick story: this morning, I was getting in an extra mountain bike ride (after I had arrived at work on said bike). I was trudging up a rocky trail, and after I nailed the 3 switchbacks, I was feeling good that I would make it to the top without having to stop. Then at some point, I let my mind wander and started thinking about the camper that I hope to buy next Spring---right when I got to the thought about how much money I should have saved up by then, I hit a rock the wrong way and had to put my foot down and stop. Bummer! For me, the lesson in that episode was, "Stop all the fantasizing about the future and pay attention to/enjoy/embrace the now!" My next thought was, "I can't wait to share that story on the MMM forum!" :-)