"For me, the most important thing in your life is to live your life with integrity," Ellen DeGeneres [1] said in 2009. She was speaking to the graduating class at Tulane University, but her wise words resonate with everyone. But Ellen's not the only celeb who's given a powerful commencement speech. Stars Amy Poehler [2], Robert DeNiro, and J.K. Rowling have also spoken at graduations over the years, and their words continue to inspire graduates and nongraduates alike.