I came across an article in Cycling Weekly about a man called John Woodburn who is still racing at the age of 72. Apparently he regularly breaks the hour for a 25 mile time trial, sometimes by several minutes. His times are impressive for a cyclist of any age. But, to get his times at the age of 72 is doubly impressive. He also still rides 200 miles a week in training.
I hope that I can ride that well when I get to 72.