Special Number 5
Frank believed that 5 was his special number. He was born on May 5, 1955. He had 5 children and lived at 555 East 55th Street. At the race track on his 55th birthday, Frank was surprised to find a horse named Numero Cinco running in the 5th race. So, 5 minutes before the race, he went to the 5th window and put $5 thousand down on Numero Cinco to win.
Sure enough, the horse finished 5th!
Source: W. Novak and M. Waldoks' The Big Book of American Humor