There are two Mexicans talking. One is a new resident of the  town. 
The first Mexican says to the other, "Hey, Vato, this town  is pretty 
rough. All the Mexicans know how to fight. So watch  your back."
 
 The other Mexican replies, "I don't need to worry, because I  know 
Mexican Judo."
 
 The first Mexican asks, "What's Mexican Judo?" The second  says, 
"Ju don't know if I have a gun; Ju don't know if I have a  knife. . ."