You get an entire upper body workout with the tuck and push combo exercise by Fitzness.com, as well as working out your abs and lower back.
You need an exercise ball for this move. Get in position as if you're going to do a pushup, but instead of your feet on the ground, place them on the exercise ball.
Lift up, then tuck in your legs using the ball, extend back out, doing a pushup as you do so. Do 10-15 reps.
Will you try this move? What parts of your body do you like to focus your workout on?