Racquetball is a racquet sport played with a hollow rubber ball in an indoor or outdoor court. Joe Sobek is credited with inventing the sport of racquetball in the Greenwich YMCA, though not with naming it. A professional tennis player and handball player, Sobek sought a fast-paced sport that was easy to learn and play. He designed the first strung paddle, devised a set of codified rules, and named his game “paddle rackets.”