Benefits: More core stability (which will help your back, your posture, everything!) and fab for super strong glutes.
How To: Start on your hands and knees, keeping the core engaged. Your hands should be aligned under your shoulders, whilst your knees should be aligned under your hips. Then, keeping foot flexed (not pointed), and knee bent, move your leg in a slow kicking motion. You should feel your glutes squeeze and your heel should be parallel with the ceiling.