BTW, kids these days don’t know what “mad dog” is. When I was a kid, MD 2020 was called mad dog. If Im not mistaken, MD stands for Mad Dog.
The Wikipedia article http://en.wikipedia.org/wiki/MD_20/20 gives M.D. as the initials of the producing company "Mogen David", and "Mad Dog" as a nickname.
I’ve never been much of a wine drinker, and even less now, but even I know MD is Mogen-David (or perhaps it’s Magen-David).