System 7 
Code Names:  Big Bang, M80, Pleiadas   System 7.0.1:	Road Warrior, Beta Cheese

 
            Floppy Disk Trick
            Insert a floppy disk and rename it KMEG JJ KS, Like Wow Man.HFS For 7.0! (where the space after 'Man.' is actually an option-space; you'll have to type this somewhere else like the Note Pad then cut/paste it into the disk name) or Hello world JS N A DTP (exactly as is).  Eject the disk using Commad-E and double-click on the ghosted disk icon.  The resulting message is “HFS for 7.0 by dnf and ksct”.  In other words it is saying “Hierarchical File System for System 7 by David N. Feldman and Kenny S. C. Tung.”

German System Hack
From: Ansgar (eszterm@sunserver1.rz.uni-duesseldorf.de)
If you open the German system 7.1, you will find in STR# -5696, line No. 33 the following: "WAS IST DAS?? STEFFEN KLAEREN!!"  For those who do not speak german, it means "What is this? Steffen find out!".

Huh?
With ResEdit, take a look at STR# resource -16415 in the System file.
The first string in the resource reads "May you code in interesting times."  This is only in System 7.  

Wheat Williams (Wheat_Williams@atlmug.org) tells what this means:
"May you code in interesting times." is a variation on a traditional Chinese taunt or insult, which goes: "May you LIVE in interesting times."  It is understood this to mean that the Chinese like their lives to be simple and mundane, and "interesting times" means times that are full of civil unrest and intrigue.

System 7 Tune-Up 1.1.1
Code Name: 7-Up
The owner resource of this third-Tune-Up release contains the question
everybody asked when it was released: "Again?".

Unused Secret About Box by Greg Marriott 
•There are more pictures and text at http://www.spies.com/greg/eastereggs.html
•Greg's home page is at http://www.spies.com/greg/ and his internet address is greg@genmagic.com

System 7 has a secret about box. I'll bet you didn't know that. Not too many people do. A short time after I joined the Blue Meanies we started making plans for a secret about box in System 7. It was my job to figure out how to trigger it, what it should contain, and how to hide it in the sources so nobody at Apple would get wise before it was too late to stop us. I talked to a few other Meanies and we came up with a pretty good scheme. The trigger was full of sevens. If there were seven windows with titles having seven letters, and a user chose the seventh menu item in a menu, and that item was currently disabled, then the secret about box would appear. Sheila Brady wrote a poem dedicated to the development team to put in the window. Darin Adler and I spent an evening implementing the triggers in the most obscure way we could devise. The code to bring up the window and the picture containing the poem were hidden in the data fork of the system file. The picture was encrypted and the decryption key was assembled in pieces by the various triggers throughout the toolbox. I did that so if someone ran across the strange looking code in the system file they still couldn't see what was in the picture. It was cool! 

Unfortunately, it had a bug. It crashed an application, and we got caught. A couple of engineers were trying to figure out why this application started crashing, and they backtracked right into our triggering code. It didn't take long for the word to spread and pretty soon we were in deep. 

I was ordered to remove it from the system.  I complied, of course, but probably not in the way the order-giver intended. I removed all of the 
triggers, but I left the code and the picture in the system file. So if you've got a copy of 7.0 or 7.0.1, there's a Blue Meanie secret about box lurking around in your system file, with no way to trigger it.