[spaceisballer]

I have memories of going to the library in the 90s to read MacWorld. Then learning that if I did a few clicks and maybe keystrokes you may unlock something with the processor. I can’t totally recall what it would unlock but it was for the Apple IIci and it’s 33mhz processor.

[amatecha]

My favorite was dragging a text clipping of "secret about box" to the desktop in System 7.5 and it would spawn a breakout game with the dev team's names as "bricks" :) fun times.

[JeremyHerrman]

Set the monitor to color and the date to September 20th, 1989. Then boot while holding ⌘-⌥-C-I to see an image of the dev team.

https://compmuseum.org/blog/iici-easter-egg/