One sentence you aren't likely to hear: "Those crunches were so much fun!"

In fact, you'll rarely hear that kind of declaration with any exercise. Which is too bad, for plenty of reasons.

But we've found three new core exercises that are indeed fun. Yes, they work your abs. Yes, they're effective. (Super-effective, actually.) And yes, they're hard. Yet despite this last concession, people absolutely love them.

How about you? Check out these awesome moves -- and have a blast, blasting your abs.

Mountain Climber with Feet on the Wall
If you're looking for ways to keep your ab workout challenging (and interesting!), then you must try the "mountain climber with feet against a wall." Yes, that's a mouthful. But this move--from fitness expert BJ Gaddour, owner of StreamFit.com--is without a doubt one of the coolest new core exercises we've seen in a while. It'll fry your abs, but it also works your shoulders and glutes. So much so, that it’ll help improve your performance at all the other exercises in your workout. “There’s no better way to train the weak spots that are holding you back in every other lift,” says Gaddour. (You can Bolster Your Shoulders, put your strength to the test--and grow bigger--with the ultimate overhead exercise.)

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Kettlebell Figure 8
The kettlebell figure 8 looks more like a kid’s game than it does a cutting-edge core exercise. But make no mistake: It’s a terrific way to train the muscles that stabilize your spine, says David Jack, director of TeamWorks Fitness in Acton, Massachusetts. And because you’re moving the weight in a figure-8 around your body, you work those core muscles from every angle. Plus, this exercise also challenges your thighs and shoulders, helping you build a healthier total-body. (Build muscle and fry fat all over with this killer Total-Body Kettlebell Workout.)

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Plank Walkup with Dumbbell Drag
This exercise is courtesy of sandbag-training expert Josh Henkin and Men’s Health adviser Rachel Cosgrove, creator of the Men’s Health Spartacus Workout Series (our legendary fat-blasting boot camp). The plank walkup with dumbbell drag is a new--and much more fun!--version of the classic plank. What makes it so novel and, more importantly, so effective? While in a plank position, it requires you to drag a dumbbell from one side of your body to another. "The plank exercise is about keeping your core perfectly stable," says Cosgrove. "Adding the dumbbell drag means that you have to still maintain core stability while you move a load back and forth, making it an extremely challenging version of the plank." (To make it even harder, you can use a sandbag instead of a dumbbell.)

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