Vitalik Buterin delivers a special presentation for the first time in London at the Ethereum meetup on October 3rd 2014.
Part 2 of this video includes a Q&A and can be found at: http://youtu.be/qM8zkzFZVok
Slides can be found at http://www.slideshare.net/ethereum/vitalik-buterin-cryptoeconomic-protocols-in-the-context-of-wider-society
For more meetups: http://www.meetup.com/ethereum
To learn more about ethereum: https://forum.ethereum.org