...I personally witnessed what was one of the very first 'Easter Eggs' in gaming. Anyone else remember what happened in "Space Invaders Deluxe" if you cleared a board and managed to save a bottom-row alien for last? I mean, we're talking 1980 here, '81 at latest.
I also used to have a Pac-Man pattern paperback, back in the day when my quarter supply was at the mercy of my tyrannical (well, more like responsible) parents. Therefore, to this day, I've never even sniffed the "Key" or "Galaxian" boards. I suck.