Widen Github Diffs. Useful when violators of 80 character lines are in action.

widen-github.js

// ==UserScript==
// @name       Widen Github
// @namespace  http://use.i.E.your.homepage/
// @version    0.1
// @description  enter something useful
// @match      https://github.com/*
// @copyright  2012+, You
// ==/UserScript==

var containerWidth = $('.container').css('width');
var repoContentWidth = $('.repository-with-sidebar .repository-content').css('width');
var button = $('<a>').addClass('btn btn-sm').append($('<span>').addClass('octicon octicon-unfold').css('transform', 'rotate(90deg)'));
button.on('click', function() {
  if ( $('.container').css('width') == containerWidth ) {
    $('.container').css('width', '90%');
    $('.repository-with-sidebar .repository-content').css('width', '95%');
    button.addClass('selected');
  } else {
    $('.container').css('width', containerWidth);
    $('.repository-with-sidebar .repository-content').css('width', repoContentWidth);
    button.removeClass('selected');
  }
});
$('#toc').prepend($('<div>').addClass('btn-group right').css('margin-left', '5px').append(button));