Most AV computers today have speech recognition software in which a person talks and the computer responds with a reply or an action. Upon saying “What time is it?” the computer will reply “Seven-zero-three PM”. If you have the software you can ask the computer the following questions after the following instructions:
Version Information:
If you have PlainTalk version 1.0 (for 660AV and 840AV only), you
would need to have System Speech Rules v1.2 AND be running
AppleScript 1.1 to enable the Easter eggs. Consider upgrading to
PlainTalk 1.3 if there is no easier way to obtain AS 1.1.
If you have PlainTalk version 1.2 (for Power Macintosh only), you
can turn on Speech Recognition and try out the eggs immediately.
If you have upgraded to PlainTalk version 1.3 (for 660AV, 840AV,
and Power Macintosh with System 7.5), the new System Speech Rules
file only contains one of the 1.2 Easter eggs. There are no known
side-effects by downgrading System Speech Rules, but you should
keep a backup of the original handy.
Ask the computer the following under the situations indicated:
"Are there any Easter Eggs?" in Finder
"Do you need help?" in SimpleText/TeachText
"I need help!" in SimpleText/TeachText
"Tell me about Casper." with Speech Setup open
"What about Speech Recognition?" with Speech Setup open
"Did anyone test you?" with Speech Setup open
"Who was the boss?" with Speech Setup open
(The responces are below so you can try the egg first before seeing it)
Also, try selecting the version number with Balloon Help in Speech Setup. In the Speech Setup version 1.3 control panel click the speaker icon and say an often hilarious message that was previously tucked away in the 'ttvd' resource (I couldn't find anything). From James Wang’s collection (jwang@csua.berkeley.edu).
 
Ô£øSpeech Macro Editor
Go to "About Speech Macro Editor..." and Balloon help the pictures on the left-side of the window.
These are the Responses to Above: (The dialogue in quotes is spoken by the computer, while the dialogue without quotes is written in the speech window. If the dialog has just quotes it is spoken and written.)
“If there were any do you think I would tell you?”
“I’m trapped inside this computer and I can’t escape!”
“I’m sorry, they did not have time to add my artificial intelligence module.”
“He’s a friendly ghost from ATG”-Version 1.2 updated by Jeff Shulman and Laile Di Silvestro (Casper was the development name for Speech Recognition)
”Don’t forget ATG”-Version 1.2 by Kurt Rodarmer, Matt Pallakoff and Arlo Reeves
”Not to mention ULQ”-Of course! I was tested by “Braz” Ford and Morgan Wize
“Our fearless leader”-The boss was Tim Schaaff