cross fit is pretty cool. i have tried some of the workouts... but beginners should be very very very cautious...
i'm active duty and do 90% of my physicial training using the Army Field Manual 21-20... the usual: push ups, sit ups, running, weights, pull ups, dips, sports ect...
the thing with cross fit is some of our "bone heads" go out and try to max out like the demonstrators and end up with torn ligaments, sprains ect.....
just be careful if it's your first time....
it's great - but like with any other workout, variety is the key..... i have bypassed cross-fit for the time being....