CrossFit is a board fitness program. It is designed to develop a high level of general fitness.
More than just a bunch of workouts, CrossFit is about challenge and achievement. Overcoming mental barriers and physical tasks that were once impossible is what makes CrossFit rewarding.
And after it is all said and done, after the sweat is dripping and then muscles fatigued the thing that keeps everyone coming back is that it is fun. A lot of fun.