PUSHUPS WITH KNEE-TO-ELBOW TUCK
After you perform the pushup, bring your right knee in to your left elbow then repeat on the opposite side. Continue until all repetitions are performed. Do a mountain climber if the cross-body move is too hard.
Think of it as a Superman hold with a lat pull. Focus on squeezing your shoulder blades and pulling with the lats as you move your arms...and keep those feet off the ground to activate your lower back.
Now...if that doesn't make you "sweat pink," then I don't know what will.
Question: If you could only have one piece of fitness equipment, what would it be?