One of the most challenging shows I've ever seen from a visual standpoint is Carmel (IN) 2002 show, "Metal." I don't know if Michael Gaines still does their drill today, but seeing them try to pull off one of his visual programs back then was just insane. The drill was some of the fastest, toughest, and most dangerous I'd ever seen at the high school level; I saw three different instances of people falling down during their finals run, one of which was a near train wreck at the end. It was a crazy fun show to watch, especially with the electric guitar solo at the end, but those kids had to be exhausted at the end of that season.
And then of course there's L.D. Bell's "King of Kings" and "Exodus" from 2000 and 2001, respectively. That suicide drill... *shudders*