I did a small presentation on "How I would explain NSX to a friend in 10 minutes" because I found out that explaining NSX to a fellow VMware administrator was not something that could be done in a few sentences. I would add a bit more today - for example, I'd like to add the convenience of having the VM's networks defined virtually and not needing to trunk a new vlan into the hosts whenever you need to create a new subnet.
It was a great "tee up" to VMware's @prabhu_b and Michael Fortuna who gave an excellent (and more in depth) session .
The full ppt is available here and hopefully I will get a video of it soon.
My friend @stalin_pena snagged a pic for me (you can see @GregLaub next to me) and we sent it out the @nycvmug handle as well :D