This video clip is recommended by Rachel's English to practice intonation. I found the content is also very good, especially towards the end.
"...So as I look around this room at people who either have achieved, or are on their way to achieving, remarkable levels of success, I would offer this reminder: don't wait. Don't wait until you make your first million to make a difference in somebody's life. If you have something to give, give it now. Serve food at a soup kitchen, clean up a neighborhood park, be a mentor. Not every day is going to offer us a chance to save somebody's life, but every day offers us an opportunity to affect one. So get in the game; save the shoes."
"...So as I look around this room at people who either have achieved, or are on their way to achieving, remarkable levels of success, I would offer this reminder: don't wait. Don't wait until you make your first million to make a difference in somebody's life. If you have something to give, give it now. Serve food at a soup kitchen, clean up a neighborhood park, be a mentor. Not every day is going to offer us a chance to save somebody's life, but every day offers us an opportunity to affect one. So get in the game; save the shoes."