Obviously crunches but a more strenuos exercise is lying down on your back on the floor with your hands at your side then lifting your feet together about 6 inches off the ground, do this till your legs give up! The weight of your legs works every muscle in the abdomin! Do this exercise 3 - 5 times a night as it doesnt take long.
Actually the best exercise for abdominals is not the basic crunch, it is a tie between doing crunches on an exercise ball and bicycle crunches. The reason these are both better than regular crunches is because using an exercise ball means you get a wider range of motion and you can work a larger section of your abdomen.
Doing bicycle crunches is a great way to burn calories and work out your entire core at the same time. You can work out your entire core because you are not doing just one motion, you work out the sides as well as the center.
These exercises may help you to get ripped in a month: Bicycle Crunches ( Legs Raised ), Straight Leg Raises ( Support your back ), Straight Leg Pendulum ( Side Abs), Butterfly Crunch ( Whole Abdominal ), Reverse Crunches ( Lower Abs), Reverse Crunches, Medicine Ball (Lower Abs), Medicine Ball twisties. Oblique (Side Abs), Medicine Ball Reach ( Upper Abs ), Bench Knee Ups ( Lower Abs ), Medicine Ball Pendulum, oblique (Side Abs), Ball Crunches (Upper Abs).
