Have you heard of the Tarahumara?  Running is their favorite past time.  They run for sport, communication, transportation and hunting.  Persistence hunting is chasing your prey until it slows down and you catch it.  During their running they may even run 435 miles in a single 48 hour session.  If you need some inspiration to go for a run, this video might do the trick. http://www.youtube.com/watch?v=FnwIKZhrdt4