Userscripts.org

// ==UserScript==
// @name           YouTube Cleaned Up
// @namespace      http://userscripts.org/users/23652
// @description    Gets right of the footer, copyright, google ads, big frontpage ad, side announcement box, "may not be suitable for minors" warning, and other annoyances.
// @include        http://*.youtube.com/*
// @include        http://youtube.com/*
// @copyright      JoeSimmons
// @version        1.0.0
// @license        Creative Commons Attribution-Noncommercial 3.0 United States License
// ==/UserScript==

// Define GM_addStyle if it's not Firefox
if(typeof GM_addStyle==='undefined') 
    GM_addStyle = function(css) {
        var head = document.getElementsByTagName('head')[0], style = document.createElement('style');
        if (!head) {return}
        style.type = 'text/css';
        try {style.innerHTML = css} catch(x) {style.innerText = css}
        head.appendChild(style);
    }

GM_addStyle("#search-pva, #watch-highlight-racy-box, #copyright, #footer, #chrome-promo, #side-announcement-box, #pyv-yva-placeholder, #watch-more-popular, .spacer, div[id^=\"ad_\"], #watch-channel-brand-cap, .confirmBox, a[href=\"/whitehouse\"], #homepage-whats-new-block, #toolbar, #player-open-popup, a[href^=\"/citizentube\"], a[href^=\"/whitehouse\"], #pyv-placeholder, .watch-ppv-label, #ticker, #watch-ugc-promo, #user_featured {\ndisplay:none !important;\n}");