There is a long discussion on the WordPress forums about how you can blank your blog page as a protest against SOPA. This is the code that I used, just put it in a text widget and add it to your sidebar:
<div align="center" style="position:fixed;width:100%;height:100%;top:300px;right:0;background-color:#000;-moz-opacity:0.8;opacity:.80;filter:alpha(opacity=80);text-align:center;font-size:500%;font-weight:bold;padding-top:20px;">
<a style="color:#fff;" href="http://americancensorship.org/" target="_blank">SAVE THE INTERNET
Stop SOPA</a>
<p style="font-size:20%;padding-top:20px;color:#fff;">This site will be blanked from aprox 08:00 GMT until 20:00 GMT 18 January 2012</p>
<p style="font-size:20%;padding-top:20px;"><a href="http://www.1stwebdesigner.com/design/how-sopa-pipa-can-affect-you/">SOPA will affect non-US sites as well as US hosted sites</a>, the domain name takedown and search engine removal will affect sites hosted anywhere in the world.</p>
<p style="font-size:10%;padding-top:5px;"> This site has been taken down in protest of bills currently being considered in the US House and Senate. Called SOPA and PIPA,
these bills threaten to destroy the Internet as we know it.
If either one passes, your favorite sites could disappear forever.
</p>
</div>
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