Couple notes on what I have been doing lately:
The Tabata Method I use during GPP is taken from Dan John
Check this article out if you got time....
http://www.t-nation.com/free_online_..._tabata_method
The sledgehammer work is done with an EZ curl bar with weight on one end! I don't own a sledgehammer and I am too cheap to buy one, so I had to improvise.
Why do I do it? Because I hate normal cardio, and I was trying to find activities to get my heartrate up inside during the winter. When nicer weather returns, I plan on doing sled pulls (with a tire, rope and weight....again, improvised, kind of like this but no where near as nice....
http://patrickhdonnelly.blogspot.com...tire-sled.html ) and farmer's walks as well.
Finally, I have been doing Chin-ups 3 times daily to "Grease the Groove" (much thanks to MaverickBU for mentioning this article in another thread)
http://www.dragondoor.com/articler/mode3/69/
I started with 3x5 (my max is 14 with BW) because it is about synaptic facilitation and the sets are not supposed to be hard. I do 1 in the morning, afternoon and evening. I add one rep each week and I am currently doing 3x7.