I actually caught myself doing this in the grocery store last night, my fiance was wondering what the hell I was doing.
I was pushing the cart (awww yeah!) and when I would get to a fairly brisk pace, I would let go of the cart and let it coast, call it pulse and glide if you will. By letting go of the cart and allowing it's stored energy be spent, I saved myself energy by not having to push a load. I estimate my CPR (calories per hour) was at least 50% above the EPA.
THEN, on the way to the parking lot, there is a ramp that goes down to the street, guess what? YEAH coasted that mug. But don't worry, I looked far ahead before deciding what my action would be, just like a good hypermiler should do. In my head this sounded awesome, now after reading what I typed.... damn I'm a nerd.