Best ab workout routine

http://sportsmedicine.about.com/od/bestabexercises/a/all_abs.htm

Bicycle Crunch Exercise. This ab exercise generally ranks at the top of the list of best ab exercises if done properly.

Captain's Chair Exercise. Another great one, but you need equipment (or creativity) for this one.

Ab Crunch on an Exercise Ball. I bet you have an exercise ball at home.