It looks like the http://corp.google.com/ page has a fun Easter egg.
The page looks like a normal error page:
But if you hover over the "What's ÜberProxy?" link, it shows a hidden Easter egg:
To show/hide the "ÜP" image, it uses a simple CSS rule:
.easter-egg { display: none; } a.footer-link:hover + div.easter-egg { display: block; }
The image is directly embedded in the HTML as a data URI:
In the old versions of the page, the image was always visible (https://web.archive.org/web/20130716091355/http://corp.google.com/):
Fun Easter eggs in the BukyVede font.
Browse ASCII art and Easter eggs.
Fun hieroglyphic Easter eggs in the Aegyptus font.
All prices listed are in United States Dollars (USD). Visual representations of products are intended for illustrative purposes. Actual products may exhibit variations in color, texture, or other characteristics inherent to the manufacturing process.