Lea Verou with some extra super fancy CSS trickery. No way we could miss linking this one up!
One of the problems with responsive table solutions, at least the ones where you are using CSS to rejigger things, is that there is duplicated content somewhere. Either in CSS or HTML.
Lea finds two ways to prevent that. One of which uses text-shadow to "duplicate" a copy of the text and move it into place. Another uses the Firefox-only element() function.
Another thing to remember: if you're forcing table elements to anything other than their natural display value (like block), make sure to use ARIA roles so they don't lose their accessibility usefulness.