3rd & 4th video from the 2014 Texas Bitcoin Conference:

What Is Proof Of Stake In Nextcoin (NXT) vs. Proof Of Work In Bitcoin (BTC) - By Tai Zen
http://prisonorfreedom.com/what-is-proof-of-stake-in-nextcoin-nxt-vs-proof-of-work-in-bitcoin-btc-2014-texas-bitcoin-conference/

What Is Transparent Forging In NXT (Nextcoin)? - By Tai Zen (Texas Bitcoin Conference)
http://prisonorfreedom.com/what-is-transparent-forging-in-nxt-nextcoin-2014-texas-bitcoin-conference/

Enjoy!
Tai Zen