Temporarily blacking out a Drupal site front page's content

Add <p><img src="PathToSomeGraphicFile-Black-64x64.png" style="width: 100%; height: 32768px; position: absolute; right: 0%; top: 0%; z-index: -1;"></p> (where the graphics file referenced is simply a small square the color of most of your text), to the top of of a pinned article. It will be automagically expanded to fill the screen width and to an enormous depth vertically, probably leaving only headlines, graphics and highlighting visible.

For example, on this site to hide the articles for the SOPA/PIPA protests, I used,

<p><img src="http://emilie.hermit.net/sites/emilie.hermit.net/files/Black-64x64.png" style="width: 100%; height: 16384px; position: absolute; right: 0%; top: 0%; z-index: -1;"></p>