Too tired to do much more, but here are my notes on the argument, in pdf format (8 pages).
I showed up for the Supreme Court Bar line at 6 AM, got No. 28. They let around 55 of us in, the rest went to the overflow room with audio but no visual. Report was that they had 60-70 seats for the general public, and since several hundred showed up, if you didn't sleep in line last night you didn't get in.
My guess is a 5-4 for us, possible a bit better but I wouldn't bet on it, and a narrow opinion by Roberts: a total ban on a class of arms violates the 2nd Amendment. The lower courts can figure out any additional inplications, and after a few years we may take another case to flesh it out some more. As Roberts pointed out, first amendment standard of review is a creation of the courts, and they took years on it.
Key event: Justice Kennedy turns out to be strongly pro individual rights. Read the notes.