Well, one thing I do which I think helps is to donate blood. I'm a universal donor so I like to think that my blood is going to do some good when I donate. Who knows, I may have contributed to saving someone's life and I'd not even know it. Check out this page on the American Red Cross' website where blood recipients share their stories and give their thanks and I can't see how someone would not feel some obligation to give.
So, go to GiveLife.org to find out when and where you can give blood and help save someone's life.