Well, this seems to be popping up all over the place.
KC over at The Diabolical Conquest got me to download the video - Right Click, Save As
However, the guys at Post Crisis had the complete story. Danny Marianino, who plays for the North Side Kings, was the man who took down Danzig with one punch, after Danzig put on some asshole-rockstar airs.
About 568 kb, a good download.