Instead of Racquetball (500 calories)...
Try Cardio Tennis (500–600 calories)
Oh, the catharsis of slamming that blue rubber ball against the walls (whack! for the impossible-to-impress client; whack! for the crash-prone browser)... but doesn't that indoor court look an awful lot like your office cubicle? Take your game to an outdoor tennis court (find one here
), where you can get some fresh air while gaining a fresh perspective. To amp up the burn, try Cardio Tennis
, which offers an interval-training approach to the sport. You'll take part in games that will ensure you're constantly swinging your racquet, as well as cardio drills like karaoke steps and high knees. Instructors say that this helps you get a full-body workout and burn more calories than singles or doubles does. (More info and program locations at CardioTennis.com