A green themed social network called Greenwala is now running a contest that I think might appeal to people who try to live a healthy lifestyle.
The contest, called "Put A Positive Spin On Your Life," asks entrants to submit a photo of them participating in some sort of healthy activity along with a brief description of how it's contributing to a better lifestyle.
Here's the link if anyone wants to take a look: http://www.greenwala.com/greenwala_contests