I love the story of Dick Hoyt and his disabled son, Rick.
"This year, at ages 65 and 43, Dick and Rick finished their 24th Boston Marathon, in 5,083rd place out of more than 20,000 starters. Their best Time? Two hours, 40 minutes in 1992--only 35 minutes off the world Record, which, in case you don't keep track of these things, happens to Be held by a guy who was not pushing another man in a wheelchair at the Time." (more from Sports Illustrated on the first video's YouTube page)
I remember when Hoyt was asked why he doesn't try it alone just one time to see how he would do against such world records, and he said it was meaningless without his son.
Story on the Today Show