TRY THIS: Elevated Wall Mountain Climber
Bored of the good old sweat-inducing Mountain Climber? Well then... add some elevation to it and it becomes deliciousy brutal!
Find a wall and get into push up position, then jog your legs back and forth. Make sure you drive the knee all the way to your chin. Add a couple sets of 50 reps (each leg) into your ab routine today and you'll thank me tomorrow!