(FORTUNE Magazine) – For most of Michelle Wie's 16 years, she has measured power in yards. But the word is about to take on new meaning for the golf prodigy as she turns pro, signs endorsement deals, and finds there is clout in product sales as well as tournament scores. Wie and others featured in this issue, from Def Jam CEO Shawn "Jay-Z" Carter to artist Stephen Hannock, are million-dollar--even billion-dollar--forces in sports, culture, and entertainment. They're building lucrative careers doing what many of us do just for fun. People who manage to have a damn good time while making their mark on the world have a special kind of power. This issue is about them.