Many tradeshows feature prominent speakers, with the 'keynote' often being used to help promote the whole event.
Examples: Steve 'Woz' Wozniak (Apple Founder, Dancing with the Stars Guy at ASIS 2013) and Colin Powell (Former General, US Secretary of State at ASIS 2014) are 'keynote' personalities.
My question to you: What is the best keynote you've heard? Has a keynote ever dramatically changed your perspective or awareness on a topic?
I'm asking about any keynote you've heard, not just security (or Dancing with the Stars) related.