|Mace Windu demonstrating|
the Vaapad fighting style.
Juyo/Vaapad, a.k.a. "The Way of the Vornskr" is the seventh of seven forms recognized as canon for lightsaber combat by the Jedi Council of the Old Order. Juyo itself was described as the most vicious form of lightsaber combat and was said to involve significant internal focus on the part of the user. Members of the Sith, such as Darth Maul, employed Juyo without reservation. You guys remember how awesome Darth Maul looked, right? Well that's Juyo.
Mace Windu created the style Vaapad from Juyo. He explained it as a state of mind rather than just a fighting style, allowing the wielder to channel his own inner darkness into the duel, and accept the fury of the opponent.
"Six there were for generations of Jedi. The seventh, is not well-known. Powerful form it is. Deadliest of all. But dangerous it is, for its master as well as its opponent. Few have studied. One student alone, to mastery has risen."
Here's a clip from the 2003 Clone Wars that shows Mace Windu
just being completely awesome. The animation is poor but it's
really fun to watch. You can kind of see the makings of the
C.G.I. Series that aired on Cartoon Network years later.