Not a joke but...

[pengipete]

...type ABOUT:ROBOTS into the address bar in Firefox 3 and then press enter. (Don't forget to test the button - despite what it says)

There are other easter eggs in FF - depending on which version of you have - including various digs at Internet Explorer. Try ABOUT:MOZILLA to see one (it's a reference to an old IE promo)

There's also a very odd one - type chrome://browser/content/browser.xul into the address bar - I won't spoil the "surprise" except to say that you can type the same address into the new browser - over and over again. Quite useless but fun - in a geeky sort of way.

 

[Phoenix]

That's pretty cool, I don't think chrome://browser/content/browser.xul works though because I just get taken to a blank page.

 

[Rakk]

...type ABOUT:ROBOTS into the address bar in Firefox 3 and then press enter. (Don't forget to test the button - despite what it says)

That's awesome!!!!!

 

[Tom DWC]

Hehe these were pretty good.

 

[pengipete]

That's pretty cool, I don't think chrome://browser/content/browser.xul works though because I just get taken to a blank page.

Double-check that - there may be something at the top of that "blank page" that you are missing.