There is a club called the "Marathon Maniacs", their goal is usually just to complete a marathon in all 50 states at some point in their lives. Some are little more hardcore and try to do 50 marathons in 50 states, in one year.
But this is crazy. Dean Karnazes is the ultimate of ultra-marathon runners. He has been featured in Runner's World several times and was one of the first people ever to run over 300 miles at one time! Although, he did admit to occasionally falling asleep while he was running.
His lastest endevour has been to run 50 marathons, in 50 states, in 50 days. Don't worry Sue, this is something that I will never have interest in trying. It's for the clearly unstable.