Get your Wikipedia back, in case you've already been tuned to SOPA news for the last few weeks. An identical copy of this file is at http://files.danpoggi.com/sopa.user.js - you can go there directly to install, or copy and paste the manual way.

sopa.user.js

// ==UserScript==
// @name          I WANT MY F#(*& WIKIPEDIA
// @description   Removes the blackout overlay from Wikipedia. Because we already know, and Congress is bound to find a way to mess with the DNS system somehow.
// @match         http://en.wikipedia.org/*
// @match         https://en.wikipedia.org/*
// @author        Dan Poggi
// @version       0.1
// ==/UserScript==

(function () {
  var css, head, style;

  css = "#mw-sopaOverlay {" +
        "  display: none;" +
        "}" +
        "#content, #mw-head, #footer, #mw-page-base, #mw-head-base, #mw-panel {" +
        "  display: block !important;" +
        "}";

  head = document.getElementsByTagName('head')[0];
  style = document.createElement('style');
  style.innerHTML = css;
  head.appendChild(style);
}());