Which D&D adventure added the most to an ongoing campaign?

[Glyfair]

I know the current trend is for the "Adventure Path" modules. A prepackaged series of adventures that are expected to be ran throughout the length of a campaign.

However, there are many more limited adventures that just include so much value outside of the direct adventure. The adventure might be finished in an evening or two, but the plots and repercussions of that adventure are felt throughout the campaign for years to come.

For me the adventure that fit this best wasn't intended that way. The Village of Hommlet was intended to be a lead-in to a longer series of adventures. However, the timing meant there were years between the initial release of T1 and the final Temple of the Elemental Evil (T1 was released in 1979, ToEE was released in 1985). A lot of DMs, including myself, ran it shortly after the release and wanting to continue the plots set up in the Village.

So, which published adventures have you ran that have had repercussions in the campaign long after the adventure actually was "finished"?

 

[Crothian]

White Plume Mountain. The map of it indicated all sorts of other places that the module did not describe.

 

[francisca]

U1. I'm neck deep in a 1e greyhawk campaign which sprung almost entirely out of the interaction in Saltmarsh.

 

[The_Gneech]

I used a large chunk of Return to the Temple of Elemental Evil combined with the Living Greyhawk information on Bissel to create the "heart" of my current campaign (a wizard school with a dark secret in the basement, so to speak).

In my new FR sidegame, I expect Mad God's Key and Box of Flumph to have some lasting effects.

-The Gneech

 

[Piratecat]

Chadrathar's Bane, from an early Dungeon. A fantastic game that gets the characters shrunk.

 

[diaglo]

published: B1 In Search of the Unknown

 

[Shemeska]

'Squaring the Circle' from Hellbound: The Blood War

 

[el-remmen]

B7 - Rahasia

N1 - Against the Cult of the Reptile God (best module ever!)
N3 - Destiny of Kings (second best module ever!)

 

[Hussar]

B2 Keep on the Borderlands. I've had lots of campaigns centered around that one.

 

[Mystery Man]

Hellgate Keep.