I made this demo to try out and illustrate some of the subtle button effects you can create just using box-shadow and borders on pseudo–elements.
Inspired by the work I saw a while back over on Beemuse (http://beemuse.com/paper) and so this is a heavily tweaked more dynamic version of those effects.
Also see Nicolas Gallaghers previous post on effects like this: http://nicolasgallagher.com/css-drop-shadows-without-images/
Tested in latest Chrome and Firefox, but no reason it shouldn't work in all latest browsers.