Stand with your feet together, hands behind your head. Take a wide step out with your right leg and lower into a side lunge, bending your right knee and pushing your hips behind you (your left leg should remain straight). Push through your right heel and stand back up, bending your right knee as you cross it in front of your body without touching the floor, turning your right heel up towards the ceiling.
As you cross your leg over the midline of your body, do a side crunch, lowering your left shoulder down towards your left hip. Lower your leg and repeat. Do 15 reps with your right leg, and then 15 with the left.