Apache is a free and open-source cross-platform web server software.
Drupal is a free and open-source web content management framework.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Lightbox is small javascript library used to overlay images on top of the current page.
PHP is a general-purpose scripting language used for web development.
Varnish is a reverse caching proxy.