This site and this challenge happened awhile ago, but the documentary is about to be released, and it is new to me, so I thought I'd post it.
In 2006, Dean Karnazes (his website here) decided to run 50 marathons in 50 states in 50 days. One of his goals was to raise money for a kids fund that tries to promote physical activity. One of their mottos is "No child left inside". (kind of cute) Sounds like a worthy cause to me.
Anyway, it is getting a bit more attention due to the release of the documentary, and I find it pretty interesting. I've never read his books, but some of the stuff I've heard is that he is full of himself. I took a look at his blog (he blogged the 50-50-50 challenge) and unless it is all show, he seems like a pretty cool guy to me. (especially if you read this post)