The Gyro-ball

At Popular Mechanics, they give the breakdown of the gyro-ball that Daisuke Matsuzaka is said to throw:

In theory, the gyroball uses a twisting release to put counter-clockwise spin on the ball (from the batter's view), making it break much flatter than other pitches.

Matsuzaka's initial outings will attract fans who simply want to catch a glimpse of the pitch whose name roughly translates to "Demon Sphere Gyro Ball." But teams that can't sign him shouldn't fear: The man who created the pitch, Japanese computer scientist Ryutaro Himeno, emphasizes that Matsuzaka is hardly the only person to throw the pitch.

"I do not know much about pitchers playing in either Japan and the U.S., but at least Mr.
Matsuzaka (with the Lions) and Shunsuke Watanabe (of the Chiba Lotte Marines) pitches the gyroball," Himeno tells PM.

Thanks to Mets Blog for the Link.