One day, a coworker and I decided that she was so close to the edge, that we could probably drive her over it.
We placed a little toy called "Gremlin" in the build, with some code that made sure it was shut off, except in the case of our friend, the "Testy Tester." What Gremlin did at random intervals was to have a weird little yellow/green guy grab the bottom of a window (as if the 'window' was a window into his room) and pull himself up to peep in and wave "hi" at you.
This was all fine and dandy in testing. Unfortunately, when the app made it out to production, heavy network made the client take six times as long to finish user authentication. Since we had the conditional shutoff code in the user authentication, this gave a chance for the Gremlin to wave "hi" at some of the users in the login dialog.
Whoops.
As the translations were often in a state of flux we had a development version that was in swedish chef (bork bork, etc). This was never put into prod. It mostly helped us work on functionality without getting caught up in the actual text (lorem ipsum style).
However, down the line we got a batch of testers that were using our development infrastructure. Go figure, one of them has swedish as their browser preference... When they got "bork bork bork" they weren't impressed to say the least. Took us ages to convince them that it wasn't deliberate.
That was in 2006. It was so well hidden in the code that no one found it until I mentioned it to someone at the company this past spring (I had hidden in the jar of a 3rd party library). Within a couple days I got a call asking how to remove it. They obviously didn't see the humour which is unfortunate because it's a marketing goldmine.
We forgot to replace it. And we won. $25k. It was probably the most honest thing we wrote in the whole plan, and the only part of it that turned out true. (except the "strapping" part)
http://web.archive.org/web/20040416123830/www.reteambiente.i... ("CERCA nel sito")
I was fired.
Back in the mid-90s I had a hidden Easter Egg in a Java Applet (the next big thing, you know) that expressed my frustration with the language even back then ( http://www.conman.org/people/spc/refs/search/search.hp1.html )
Shortly after that, I added another one in the HTML page for the rewrite to that product (no longer a Java Applet) that, amazingly enough, people found and tried to use ( http://www.conman.org/people/spc/refs/search/search.hp2.html ).
And for the past fourteen years I've included an HTML comment on some of my webpages and I've only had one person find (or at least, one person find and comment about it).
http://img523.imageshack.us/img523/9836/egg1by2.png
http://img523.imageshack.us/img523/7530/egg2zu2.png
http://img523.imageshack.us/img523/8361/egg3mv6.png
This is an internal beta, this stuff will be taken out from the the production release.
Although i left close to two years ago,and it really is'nt much of a deal - it still brings me a hint of wicket satisfaction that 'each and every' chat/whiteboard message spread across 107 countries, gets wrapped in between my cellphone number : )