One of the coolest parts of the show was when David picked up a Guitar Hero controller for one of the songs. They had modified it so that it would play samples, and had sampled the I, IV, V, and VI chords and a couple of special effects, so he was able to play with the song just fine. I'm reading some of the forums now to see how feasible it would be to create a similar controller. So far, it's fairly promising.
Also, partway through the show, Mark took a picture for their twitter feed. If you look close, you can see me and yarbiedoll's arm. If I get around to it, I'll make a copy of the picture and draw an arrow to me. If you want to play "Where's drmellow?", narrow your search down to the lower right quarter and you might be able to find my pale, bearded face, wearing a blue shirt.
After the show, we stood in a long line to get everyone in the band's autograph. David even posed for pictures with us. They're on my friend's camera right now, but when I get copies, I'll post them.