This video was taken a few years ago at Yuba City High School (CA). It is one of the most powerful clips I have seen, and illustrates the power of words and messages in a way that very few speeches or presentations can.
Challenge Day is the organization that created and operates the Challenge Day program at schools across the United States – check it out.
There is also a communications lesson here – Challenge Day effectively illustrates how to a) craft a very powerful message and b) make it very easy for everyone who comes in contact with the message to personalize and internalize it. Very powerful and very effective!