I'm a sucker for prog bands doing the acoustic thing so this really caught my ear. I don't know that I've seen this posted anywhere so here is Firefly unplugged. Also, some of you can confirm this, but I think I saw Jim Matheos almost smile.
https://www.youtube.com/watch?v=3NrCTIQ64F8
https://www.youtube.com/watch?v=3NrCTIQ64F8