This exercise is great for the entire abdominal area and especially for your side abdominals.
Lie flat on your back and overlap your fingers behind your head. Bend your knees about 60 degrees and keep your feet flat on the floor and about shoulder width apart.
Apply up and side motion. Curl up and bring your left shoulder across your body while bringing your right knee in toward your left shoulder at the same time. Try to bring your body and shoulders toward your knee