While there's nothing wrong with basic ab and oblique exercises, some of us are always wanting more. Here are ten unconventional (but very challenging) core movements you've gotta try.
Don't have a rope or a sled? Try it with a band.
Too easy? Try the bipod plank:
Instead of picking one limb off of the ground, you'll pick up two... opposite limbs, obviously. If you can stay in position and raise the same-side arm and leg, make sure to take a video.