This video shows you how to do a basic ab wheel rollout, that is effective becuase it needs your whole upper body to do work in order to be done, so it not only touches on your abs and core, but will help build muscle in the whole upper body, including shoulders, arms and back!
This is definitely one of the more effective alternative over crunches or sit ups. Try to work up until a point where you are doing 20-30 of these roll outs and so that you maybe even can do them on your feet, which would be ideal.
