Best. Easter Egg. Ever.
That is the code that unlocks the coolest easter egg in a technological device, ever... What is it? The Ms Pacman / Galaga cabinet includes the original Pacman.  
The other day when I was researching Ms Pacman / Galaga arcade cabinets, I discovered that Pacman is also on the machine as an easter egg. Last night I got a chance to try it out at a bar/restraunt down the street from me. I put in my quarters, entered the code, the ghost on the screen changed colors, and I pressed the ms pacman player one button, and bam, I was playing Pacman.  
I'm fairly certain I was the first person to ever do this on this machine, cause the high score was still at it's default score of 10,000. Needless to say, that high score is now a lot higher. Though I doubt there will be many, if any, other challengers on this machine.  
The new Ms Pacman / Galaga machines have an option to make the ms pacman game go faster than the original. Which is great, because this improves my ability to track the ghosts. This "speed up" translates into the pacman game as well.  
Runners up for best easter egg:  
pong on the kurzweil k2000/2500  
that dude's name in Adventure for atari  
the thriller video on the Final Fantasy DVD
old arcade games
affiliate19: clu i don't know what you ended up finding, but in 1999 i lived in fullerton, ca, and there was a place there called "The Reagan Years". it was owned/operated by an extremely cool and laid back guy named Shawn, in conjunction with a coffee shop behind it called the Hub. the only reason i bring it up is because for a while it was one of the largest collection of old school arcade games out there, and i know for a fact that every game in there had a price tag on it. that was how he kept the place open, selling off a game or two a month. and they were cheap!  
anyhow i know the place is still open, but i don't know what the status of his retailing is. i think the popularity of the place sort of picked up over time, and in three years who knows.  
but if you wanted to try, he might be able to give you a couple leads on how to find what you're looking for. i think he'd be excited that somebody was interested in preserving something like that.  
(714) 871-2233 Ask for Shawn or Carlo.  
good luck!
clu: Thanks for the nfo. I'm very interested. I'll check them out. Though its a hobbie that I can't really afford to get into for at least a few years. In the meantime, I'm just gonna have to worship my Tron cabinet. /me loves his Tron cabinet. /me must learn to overcome his fears and fix the damn thing.
ultrafastx: Thriller video on the Final Fantasy DVD?!
clu: They animated the characters from FF to do the thriller dance. It's not the whole song, just s small bit of it. But it's still pretty damn cool.
ultrafastx: Hmm...I think I'm gonna have to go find that easter egg.