<blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="http://meta.stackexchange.com/questions/28625/whats-the-joke-in-the-stack-overflow-404-page-code">What's the joke in the Stack Overflow 404 page code?</a> </p> </blockquote> <p>For example:</p> <p><a href="http://stackoverflow.com/questions/does_not_exist">http://stackoverflow.com/questions/does_not_exist</a></p> <p>What is the code on the right pane, and if it is a real language, what does it do exactly?</p>