No, this is not your mind on drugs. It is actually a nifty HTML Graph Applet created by Sala, who says that more than one million graphs have been made since it was put online. Insert a simple url and comes up with some amazing patterns. Because it works with flash, if you have an older computer, it will take some time to come up with the final image.
Here is the translation for the colors:

• blue: for links (the A tag)
• red: for tables (TABLE, TR and TD tags)
• green: for the DIV tag
• violet: for images (the IMG tag)
• yellow: for forms (FORM, INPUT, TEXTAREA, SELECT and OPTION tags)
• orange: for linebreaks and blockquotes (BR, P, and BLOCKQUOTE tags)
• black: the HTML tag, the root node
• gray: all other tags