Stick the egg in a smallish plastic container, probably maybe 1.5 to 2x the size of the egg. Fill the container with egg about halfway with water. Put the lid on and shake firmly (lengthwise along the egg) for about 10 seconds.

I dunno what it is about this technique, but it makes the shell MUCH looser from the egg. Doesn't work great for runny eggs though since it tends to pop them.