Summer is a good time to replace bad habits with good ones. We all have more free personal time because all our favorite shows are in re-runs or replaced by vapid, pointless reality programs. Yes, you could start exercising again, and volunteering for a worthy organization is always a great idea. But if I could offer you one little piece of advice it would be the one thing that will benefit you as much as it will benefit me.
Read more books and watch television less. :-)