Go For a Run.

If you don’t think you were born to run you’re not only denying history. You’re denying who you are.
— Christopher McDougall, Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen

It's gorgeously cool and sunny down here in Atlanta. If your weather comes close to being like that, you should go for a run. And if it doesn't come close to being like that, you should still go for a run. Why? Because running is one of the most natural, healthy movements you can do. Even if you don't get "runner's high," you'll benefit from challenging your body to move the way it was made to. Even if it's just for 10 minutes. Even if you walk instead of run. Just get out there and go.

There’s something so universal about that sensation, the way running unites our two most primal impulses: fear and pleasure. We run when we’re scared, we run when we’re ecstatic, we run away from our problems and run around for a good time.
— Christopher McDougall, Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen

And here are two other guidelines to complete the challenge:

  1. Don't listen to music. Listen to the world around you. Listen to your breathing. Listen to the voices inside your head. On this run or walk, just be.
  2. Breathe through your nose. Keep your mouth shut. Inhale deeply and exhale slowly. This may slow down your pace, but that's OK. You will feel calmer and stay more aerobic, and both of those are good things.
If you don’t have answers to your problems after a four-hour run, you ain’t getting them.
— Christopher McDougall, Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen