Racquetball is a racquet sport usually played indoors in an enclosed court. Other variations of racquetball can be played on one, two, or three walled courts outdoors. <p>Racquetball is an offshoot of squash, which is popular in the European countries. <p>The racquets are shorter than tennis racquets and the ball is made of rubber. <p>Racquetball is a fast and exciting game which has turned many players into hopeless, hardbodied addicts of the sport. <p>Because of its starting and stopping characteristics, racquetball is not considered to be an "aerobic" sport by definition, although it definitely can contain an element of aerobic exercise.