Show a node (content) in a light box D7
You will likely want to define a custom page.tpl.php for use in the lightbox so it doesnt conflict with your normal site pages where you would like sidebar content etc.

Think of having 2 differently themed versions of the same page, your traditional page and a cut down version which is only the node content area.

To do this, add a theme_preprocess_page() so it creates a unique url argument to trigger the content only display via its own tpl.php:

function YOURTHEME_preprocess_page(&amp;$vars) {
  // Get the path (eg node/#) and split it into an array ([node][#][video])
  $path = $_GET['q'];
  $path = drupal_get_path_alias($path, $path_language = '');
  $patharray = explode('/', $path);

  // If the last part of the path is "frame" use the page-content.tpl.php
  if ($patharray[2] == 'video') {
    $vars['template_files'][] = 'page--video';
  }
}


Then copy your exiting page.tpl.php into a page--video.tpl.php and trim out all the content you dont wish to see in your lightbox.

EDIT: (include details on using the video only page) In your iframe load your node page with "video" appended to the drupal url. For example "node/135/video" so it using the page--video.tpl.php

I have been using this solution to embed content from our nodes into another application and it works well. :)