Examples of hard work/dedication

I'm looking for some stories online about people who are examples of incredibly hard works and discipline. For example, stories about how hard olympic athletes train or how many hours people put in starting companies. I'm not necessarily saying working 100 hours a week is the right thing to do but nevertheless am looking for some examples of people who do this (like the link to the story about Jeff Immelt below):

Fortune 75 - GE's Jeff Immelt: The Bionic Manager - Intro - FORTUNE

Anybody have a few stories you'd like to share?