Check out Clarence Hartley. He is simply amazing to be concise. For decades, he's had the goal to compete in the pinnacle of runs - the Boston Marathon, and finally, at 81, his dream came true. He is a cancer survivor, retired Air Force veteran, an elite runner, and obviously an inspiration. He pretty much proves that you are NEVER too old to go after your dreams.
http://www.runnersworld.com/cda/microsite/article/0,8029,s6-239-506-0-13907-0,00.html?cm_mmc=Facebook-_-RunnersWorld-_-Content-Boston-_-ClarenceHartleyBostonMarathon