Old Greyhawk Castle, Level 6

 Labyrinth. or, "The Black Dragon Level"

A repeating maze with dozens of wild hogs (3 dice) in inconvenient spots, naturally backed up by appropriate numbers of Wereboars. [3]

At the northern end were a series of large chambers, while to the south lay a number of mazes populated by monsters such as wereboars and, of course, minotaurs. The large chambers had four exits in the cardinal directions. Separating these were large areas of seemingly solid stone and each blank zone held a secret door leading to a repository of magical goodies that contained only one type of treasure---potions; scrolls; magic armor, shields, and weapons; and gems, money, and non-magic items. In addition to the treasure troves, two black dragons were held in stasis in similar caches, purple worm may be "allied" to the mated dragon pair (black dragon and purple worm battle by Robilar in second run). A black pudding that made its lair in a hollow passageway and dissolved Robilars boots of flying upon entering the level.

This level was a labyrinth with a lot of were-boars and other shape-shifting creatures lurking around. To the east were several large open areas, all alike of course, and on the western faces of the seemingly solid stone forming these big chambers were secret doors. These accessed six rooms. These hidden places were filled with gold, jewels, scrolls, potions, other magical items, and enchanted weapons. All save two, that is. The second and fourth of these held a mated pair of the oldest and largest black dragons held in stasis, freed when the secret door was opened, that also lowering a wall section for the good dragon to exit. [15]

After the two dragons were by accident both freed by the greedy treasure hunters: 

They had discovered previously that there was a shaft that went upwards several hundred feet in the far eastern portion of the level. 

With an overall level depth of 50 feet. This would indicate that several hundred feet would span at least four levels, which from level six would be all the way up to level two or even level one. Unless the level was offset to the side, the round room at the very north-eastern corner of level one and three would fit the description "in the far eastern portion", and also the admonishment that unusual areas and rich treasures should be relatively difficult to locate, and access must be limited [1].

Robilar, sparated from the others would have the first check for a random monster, of course, seeing as how there had been considerable commotion. [...] A purple worm was indicated, and it could be only one place .... coming down the shaft! [15]

In his haste to allow his character to escape, Rob forgot that the passageway down which he said Robilar was fleeing happened to be the very one in which a large black pudding had taken up residence in a depression on the floor. It ate those boots of levitation off his feet as Robilar ran across, and delivered sufficient additional damage to put the poor fighter near his end. [15]

In the previous looting the three discoverers went up a couple of levels each [...] from which lesson I learned never to have so much treasure so unguarded. [15]

As to the tale of the black dragons in Castle Greyhawk, I do not want to go into great detail now, as something similar will be found in the Castle Zagyg dungeons ro begin publishing late this summer and on into 2008. Here is a precis of the tale.

My excellent veteran players--Ernie, Rob, Terry, and one or two others explored a level of the dungeons and accidentally discovered a series of secret chambers in which were stored treasure and magic items. They looted all of these repositories. Of course being greedy they searched for a new secret room...and found and deleased a dragon instead of wealth.

After failing to subdue it, taking breath damage twice, they ran for their lives. Robilar slung his subdued gargoyle flunkie over his back, and when the dragos spit acid at him, the gargoyle turned to goo, but Robilar took only one-quarter damage. He then have the dragon the slip, used his Boots of Flying to ascend a vertical shaft, but by random chance a purple worm was descendiing ths same route. Roblilar dropped down in a hurry, went for a normal exit passage, and was spotted by the dragon. At that Robilar ran full speed, forgetting there was a black pudding on the floor ahead, and his flying boots were "eaten."

As the rest of the party had escaped without loss, they returned for more loot. Instead they released a second dragon. After that the mated pair of drakes ruled the level and the adventurers shunned it assiduously. That saddened me as the DM, as the lot of them had gained a full level and about half the number of XPs to go on to the next.

What annoyed me most was that all of the different repositories were discovered by luck, the mapper thinkingthat he was leading the party to the original place each tome, but actually being off course. Naturally, luck lead them to the ones with much treasure before their greed brought them to the ones holding a dragon in stasis :] #7726

[References: see Greyhawk References]