wave discs
This type of disc is fitted as standard to the new Kawasaki ZX10R superbike.
Apparently, they have several advantages over regular discs
1 They prevent glazing of the brake pads by cutting away any glaze
2 They have better cooling properties than regular shaped discs
3 They are less prone to warping after hard use.
Personally, I have never tried them but I know of several racers who swear by them. They claim less fade and better stopping although they use pads more quickly.
Ferg