I participate in sports and activities that are out of the ordinary. Windsurfing has been a long term passion and I've recently taken up kiteboarding, not exactly the sports one expects an older professional guy to do. I push my limits when I ski. Otherwise how can you get better? I guess that reflects on my young outlook on life. My friends tell me that I don't act my age.
Even so, I recently took up golf. I resisted it for years and years, thinking that it's an old man's game/sport. I found that golf is an addicting pastime. It has the classic intermittent reward/frustration that sucks one in. If one has the patience and the desire to always improve, it's hard to turn away from. I study it, always trying to improve myself.
Not only is it important to get out of the comfort zone with physical activity, it's also important to keep learning. I think that if you stop learning, you start to die, and I'm not ready or old enough for that. I moved to San Francisco and enrolled in law school and wow that, certainly stretched my mind and put me way out of my comfort zone!
Update 5/2014: Graduated from UC Hastings College of the Law!
Finally, being out of my comfort zone means that I'm here... and that I'm ready to find that woman with whom I can have that kind of relationship.
I hope you're out there somewhere!