Something for possible implementation...

[AlP]

Mission acoomplished. Flying spaghetti monster overruns HAF board! Smilies turn into monsters when you type the sequence "happysmilies":
[attachment=1:3vmk9g2o]smilies_to_fsm.JPG[/attachment:3vmk9g2o]

Monsters detach from post and follow the mouse when you click them:
[attachment=0:3vmk9g2o]fsm_follows_mouse.JPG[/attachment:3vmk9g2o]

You can't see the mouse though because it wasn't taken as part of the screenshot.

I did it with this Greasemonkey script.

If you don't know how to work Greasemonkey, there's a simpler demo here.

[Recusant]

Hmm.  I was able to get your easter egg to work in Chrome on your test page, but not here.  Maybe I'm doing something wrong.

[AlP]

Hmm. I was able to get your easter egg to work in Chrome on your test page, but not here. Maybe I'm doing something wrong.

It uses Greasemonkey so you would need to use Firefox. Then install the Greasemonkey addon. Then install this Greasemonkey script. Then it should work. Hopefully Chrome will support Greasemonkey soon. I prefer Chrome as a browser.

Here's your post with a flying spaghetti monster .

[attachment=0:1kiqbboh]recusant_with_fsm.JPG[/attachment:1kiqbboh]

[Whitney]

Hmm.  I was able to get your easter egg to work in Chrome on your test page, but not here.  Maybe I'm doing something wrong.

Here meaning the forum?  That's because I haven't included the code yet.

[SektionTen]

I think it's important that the easter egg doesn't get in the way of funcionality of the forum. If it did, I would get annoyed reeeaaally quickly.
...don't hurt me.  

[PipeBox]

It won't get in the way, because you're not likely to type "happysmilies" in going about your business.  Besides, it's not an easter egg if it's blatant and always in your face.