Idea for longer quest:
Similar to what WoW did with opening portals to content:

The Empire's armies need your support! Gold is always needed but beyond this we need the following:

XXX number of items containing such and such an effect must be donated to the cause.
(A/b/s, heal, cure for X effect, resistance to such and such)
The death of X of Y cabal
An anti paladin's weapon containing 50 charges.
Tiamat's five color mail
The orb of the order lords
(etc.)

Each cabal to be given their own long list of requirements, with progress shown to the entire mud via cabalwars or such. Even if this was just an Empire vs Fort or Outlander, for a single area to either reflect a more imperial design or be purged of evil for a a year, something we could do that resulted in changes to the areas of the game (even if just the flavor).

Quicker version. The first group of players to acquire items placed in the following locations: Boss of area A, Boss of Area B, hidden item X in zone y, and of course 500 gold will be allowed the right to battle and the Hydra, which has unique reward for completion.

Puzzles:

Encrypted messages
I've just written a role for my character with an encryption scheme in it, that can be done inside CF pretty easily. (i've got a lot of time on my hands right now as I'm on paternity leave for the birth of our first child.) Something like this could be expanded upon. Run a quest in which scrolls are showing up randomly with this cipher text on it. Inhabit a scholar mob that would give hints to players if they get stuck or if they pay him with gold, etc. To keep the quest moving.
The words if deciphered could have some short term in game advantage, like allowing players to use the Spire teleport system between cities or such. Where people would want that advantage, even if it gets spread by word of mouth after being deciphered.

CF specific riddles on newbie channel
This was fun when Twist did his history of himself questions. Generate some CF specific riddles, that require in game knowledge, the answers to which would possible provoke people to want to go and find that place or item.

Eg,
This is the lowest level item too powerful for a container which adds 25 to health?
You can't see anything! and you are fighting a vampire, where are you?