This talk was modeled after an ongoing series of lectures where top academics are asked to think deeply about what matters to them, and then give a hypothetical "final talk," i.e., "what wisdom would you try to impart to the world if you knew it was your last chance?" (http://en.wikipedia.org/wiki/Randy_Pausch)
In this lecture, he talks about the importance of having fun and working towards attaining your childhood dreams. In the process, he delivers a concise but eloquent summary of how to lead your life.
http://www.youtube.com/watch?v=nwO7EnM0zWM