Html5shiv - HTML5 IE enabling script. Dual licensed under the MIT or GPL Version 2 licenses Full original, uncompressed source available here: Source code adds new HTML5 elements (which is simple code), but also supports printing HTML5 elements and includes the default styles for HTML5 elements, like block on article and section.
Getting it to work in the browser was easy, @jon_neal and afarkas made IE actually print HTML5 elements - these guys are to take all the credit. aFarkas/html5shiv. HTML5OpenRef. HTML5 Please.