Randy Pausch Last Lecture: Achieving Your Childhood Dreams (2007) [video]
Georgia Tech set up a room in the CS department for a live broadcast of this lecture when he gave it.  I had just started as a brand new freshman a month before, and happened to find out about it / check it out on a whim.I truly do not think it is an exaggeration to say that it changed the course of my life.  I was frustrated and angry with all sorts of things when I walked into that room, and I still was after I left, but in that hour I saw a glimpse of what life could look like if I stuck with it through the hard stuff, and it was the first thing in a long time that really got me genuinely excited about my future.I will forever be grateful to Randy Pausch for his positive attitude and for his willingness and effort in sharing this when he did - especially since he never got to hear the gratitude himself directly from me or so many countless others I know he impacted positively as well.  I am strangely emotional just thinking about it again now - a bright light of positive memory in a dark year.