Where to start?

One of the things that can be initially missed when people look at CrossFit.com is how we scale our workouts to suit those who aren't as fit as they could be. Some people can be under the impression that they aren't fit enough to start doing what we do-all that we do is scalable, if you can walk and sit you are fit enough to start training.
All new clients start on the nursery slopes, learning movements, and getting accustomed to how we work and intensity in all its relative levels.

Mark's workout
5 Front squats
7 situps
run 140m
x 5

Mark comes from a rowing/traithalon background so as a result he is more conditioned than an individual who has done very little exercise but this workout can be further scaled to air squats (unweighted) and less situps (if at all) and shorter runs (or even walks). You don't need to be fit to start CrossFit but if you want to be it's the best way to do it.