This beastly exercise comes courtesy, again, of Nick Tumminello. This guy just has a knack for developing exercises that I find to be extremely effective.
What it is: The Push-Back Push-Up
Why it is sick: Mainly because it is another new push up variation, and push up variations are beastly. One of my favorite things to do is take guys who think they are advanced well beyond the point of even thinking about push ups, and just stapling them to the ground with different variations.
"Oh, you can bench 135x12? Cool, try this feet-elevated spiderman pushups and tell me how they go....muahahahahahahaha"
This push up variation is sweet because, unlike most other variations, it adds two dimensions to the exercise. You get the standard push up, and then the push back works your chest, lats and serratus unlike any other push up I'm aware of. Add the fact that you are moving your body back and forth (think bodysaw) and you are engaging all of your core musculature beyond the needs of a normal push up. This is a great way to finish off an upper body workout and hit your muscles from multiple angles at once.
Go give it a shot!