Looking for a new workout? If Tae-bo and the now trendy capoeira don't do it for you, how about the Filipino martial arts discipline Kali? A buff Matt Damon was schooled in the technique to play a master assassin in "The Bourne Identity," which opens in theaters tonight. Fight and stunt coordinator Nicholas Powell, whose credits include "Enigma" and "The Mummy," schooled Damon in Kali's finer points. "It's very quick blocking, trapping and destruction techniques," explained Powell. "You don't see it on film very often, which was exactly its appeal." So after five months of training, is Damon a Kali master? He's not so sure. "I learned enough to get my ass kicked," he laughed.