Racketball is one hell of a great sport to play and gets the cardio & reaction times peaked quickly. I tried it out last year with friends at the gym, and there are leagues to begin at various levels of skill. Very easy game to pick up, very intense, and cheap enough to buy a racket and a couple of balls if your gym has such a facility at hand to you.
If anyone in the Ottawa or Montréal area is interested in playing a Racketball rookie, give me a PM