Dean Karnazes is on the verge of accomplishing something rather spectacular. For the past 41 days, he has run a marathon every single day in his Endurance 50 quest to run 50 marathons in 50 days in all 50 states. Yesterday, he was in Louisville. Today, he was in Atlanta. Tomorrow, he'll be in Largo, Florida before making his way to Washington, DC for the Marine Corps Marathon on Sunday. Then, it will be just one week and six more marathons up and down the East Coast before the grand finale, as Karnazes runs side by side with Lance Armstrong in the granddaddy of them all, the ING New York City Marathon.