It happened yesterday. Seems like it went pretty well, too.
No time for long rants, so here's some short ones. :P
1. I predicted they'd downtune everything as soon as I heard they were doing this concert. I appear to have been right.
2. "Stairway To Heaven" sounds pretty good detuned.
3. Plant's voice has aged better than Dio's.
4. It's called Just For Men, Jimmy. Look into it. God, there's nothing more depressing than an aging rock god. :P