Firefox Users
 

Simply some stuff that will make you laugh while taking a break from your hard code:

type these into your address bar:

about:robots
about:mozilla
about:config

Kitchen Sink - Was never included in Mozilla for the reasons listed in Bug 122411 ("Mozilla does not have a kitchen sink"). You can install an extension that adds it though :D

The button that they tell you not to press on the robots page should do more. Like make the tab explode or something. Something neat.

New One:
chrome://browser/content/browser.xul

Pretty random stuff! They should have warnings that pop all the time if IE6 is installed on your computer :D