What is CrossFit? Make yourself read this.

Crossfit is not a specialized fitness program, but a deliberate attempt to optimize physical competence in each of ten recognized fitness domains.
Endurance - The ability of body systems to gather, process, and deliver oxygen (cardiovascular/respiratory endurance).
Stamina - The ability of body systems to process, deliver, store, and utilize energy. (capacity to maintain repetitive muscular movements)
Strength - The ability of a the range of motion at a given joint.
Power -muscular unit, or combination of muscular units, to apply force.
Flexibility - the ability to maximize The ability of a muscular unit, or combination of muscular units, to apply maximum force in minimum time.
Speed - The ability to minimize the time cycle of a repeated movement.
Coordination - The ability to combine several distinct movement patterns into a single distinct movement.
Agility - The ability to minimize transition time from one movement pattern to another.
Balance - The ability to control the placement of the body’s center of gravity in relation to its support base.
Accuracy - The ability to control movement in a given direction or at a given intensity.
Crossfit works exclusively with compound movements and shorter, high intensity cardiovascular sessions. We’ve replaced the lateral raise with push-press, the curl with pull-ups, and the leg extension with squats. For every long distance effort, our athletes will do five or six at short distance. Why? Because compound or functional movements and high intensity or anaerobic cardio is radically more effective at eliciting nearly any desired fitness result. Our approach is consistent with what is practiced in elite training programs associated with major university athletic teams and professional sports. CrossFit endeavors to bring state-of-the-art coaching techniques to the general public.
Adopted from Crossfit Journal October 2002