I find on some Drupal sites that I want to see information all the time behind the scenes, but I don't want the client to see. I added simple code to allow me to do just that. While it is true that I can use the Devel or Devel Themer modules, there is some information that I want which is not provided by Devel, so creating my own custom code works. This code can be embedded into a block, module, or in just the page.tpl.php (or any page template suggestions).
Now, to make things simpler in this tutorial, I embedded inline CSS, but you can obviously add this to any .CSS file.
$username = $user->name ;
// Generate all your Drupal and PHP variables
$nid = arg(1);
$alias = drupal_get_path_alias();
// Print out your HTML div tag with inline CSS or CSS class attribute