A modification of Lifehacker's Invisibility Cloak

Need to curtail your surfing during certain time periods?  I've tweaked Gina Trapiani's original code to make it a little more tolerant. 

Put a few numbers into the "surfHours" array and you'll be able to access your "blocked" sites for one hour after each hour listed.  As an example, if surfHours = [9,13,17] you can access facebook (or any other site) from 9-10am, 1-2pm and 5-6pm.

You can install the script directly from userScript and the source code is below.  If you don't know how to install a grease monkey script, check out the instructions at http://userscripts.org/scripts/show/92640

// Invisibility Cloak
// version 0.1
// Gina Trapani
// 2006-01-03
// Released to the public domain.
//
// ==UserScript==
// @name          Modified Invisibility Cloak
// @description   Turns time-wasting web pages invisible until a specified time of day.
// @include       http://flickr.com/*
// @include       http://*.flickr.com/*
// @include       http://metafilter.com/*
// @include       http://*.metafilter.com/*
// @include   http://*.facebook.com/*
// @include   http://*.twitter.com/*

// ==/UserScript==
//
// ==RevisionHistory==
// Version 0.1:
// Released: 2006-01-03.
// Initial release.
//
// Version 0.2
// Released 2010-12-13
// by Dan Fishman
// allows surfing on "invisible" sights for one hour after each number in the 
// surfHours array 
// ==/RevisionHistory==



(function () {
// EDIT THE NEXT LINE TO SET THE HOUR AFTER WHICH SITES SHOULD APPEAR
// HOURS IN MILITARY TIME, SO 15 = 3PM
 
     var surfHours=[9,13,17];
     var tstamp = new Date();
     var hours=tstamp.getHours();
     var okToView=false;
 
     for(var x=0;x<surfHours.length;x++){
        //alert("hours=="+hours+" sh="+surfHours[x]);
    if(hours-surfHours[x]==0){
            okToView=true;
        }
     }
     if (!okToView){
 var b = (document.getElementsByTagName("body")[0]);
 b.setAttribute('style', 'display:none!important');
 //The alert gets irritating on sites that link back to facebook 5 times.
        //alert("You can surf from 9-10, 1-2 and after 5");
 }

})();