When I first started working at AOL back in 1997, one of the things that I worked on was "aoltray.exe" for the AOL 4.0 software. aoltray didn't do too much, other than launch the AOL software, but it seemed like a clever place for an Easter egg. I discussed this concept with the product manager for AOL 4.0 (codenamed "Casablanca"), and he gave me the go-ahead to implement an easter egg. (It was the late 90's, when products like Word, Excel, and IE had elaborate easter eggs. But I digress).
So, I got together with a pair of artists and we came up with the idea of having the tray icon AOL logo split open, revealing a dancing running man, all set to a techno music score. The artists did the illustrations and the music, and I coded it up into the aoltray code. This shipped out in some of the AOL 4.0 beta builds, and we all thought it was pretty cool. Well, almost all of us.
Eventually somebody showed it to one of AOL's senior executives, who was most displeased with it. The exact reasons why he didn't like it were never known, but the message was sent down that this sort of tomfoolery was a fireable offense. My career at AOL could have been very short, but fortunately my management chain played dumb and didn't give up my name (thanks!).
Anyway - Jason, Erik, and I thought this thing was pretty cool, and it's a shame that only a few people ever saw it. So here it is, for your viewing pleasure. If you run this application, you'll see an AOL icon appear in your system tray. Hold down "A", "O", and "L", and double-click the icon. Then sit back and watch! (See the 3 screenshots to the left to get an idea of what happens. Note that this thing does play sound, so you might want to turn down the volume if you're in an office environment)
Update 10/07/2006 2:08 PM PDT:
Some people have reported that it doesn't work for them. I forgot, back when we originally did this we noted that some keyboards would not indicate properly that 'A', 'O', and 'L' were all being held down. So I have uploaded a new version, where you can just hold down Ctrl and double-click the AOL logo.
The entire app is contained in the EGGTRAY.exe file, which is only 43 K - to uninstall, just delete the file.
If you can't seem to get it to work, you can check out the (somewhat less cool) web version of the easter egg.