Here there are a couple of videos of the same talk "Simple, made easy", by Rich Hickey. I love Rich's talks, and I think it's even enlightening seeing the same talk twice, fine tuned for different audiences.
First one is from RailsConf 2012 Keynote. Done with a ruby audience in mind.
Second one is from StrangeLoop 2011. much more hilarious and punchy IMHO, and maybe a little less serious tone, but equally enlightening.Here it is. bye!