Easter Egg from Exile III: Ruined World
One of the best games I've ever played is the Exile Trilogy from the mid nineties. It might have low graphics, but it has one of the most detailed worlds I've seen yet in a game (except for possibly Spiderweb Software's remake: The Avernum series). It shuns a linear story and has enough side-quests to keep you occupied for at least an extra month. Here is the tale of one of the most awesome side-quests I've ever come across.
Finding the easter-egg dungeon is a pretty difficult task. The start of the mission is so hard to find it's almost impossible to start (unless you've cheated and given yourself all the keys). You start off with a wild goose-chase in search of a potion recipe. You go from one NPC, including one that randomly appears in different towns. The last townsperson tells you that the recipe can be found in a secluded monastery, and sells you the key to the front door.
Let's go check this place out. To get there we ride a ship on a small port town to a nearby island with an even smaller village named Gebra. Gebra is where the weirdness starts. For some reason the villagers act like mindless automatons. None of them have names, they are all just "Gebrans". Here is a typical conversation with one of them:
There is one sane person in the town: the greeter.
A welcomer who promptly and politely urges you to leave? Now this is strange. By now my this-is-going-to-be-an-awesome-adventuring-place sense is tingling. Exploring the rest of the town, I reach an area boxed off by trees. Incredibly suspicious. I walk into all the trees, and sure enough one of them is fake. Inside the secret niche, there's a small bunker filled with robes, clubs and "mad monks" who attack me. Here's the emptied out bunker:
"The chest contains papers. Lots of them. They are covered with dense, handwritten writings. You can't make much sense of them. They seem to be about avoiding the End Times, strenuous self-denial, and the phrase, "Feisty Slap of Pain".
Of course we have to follow this through, so let's leave the town and travel further down the island chain.