Listening to DF talk, I was specifically struck by Toady mentioning the problem of your party knowing when to be serious, I thought that a good solution might be to have a game-aware journal.
This journal would be able to keep track of both your quests and your personal goals.
Personal goals would be entered by selecting from a set list of things to do (conquer, master, befriend, kill, survive, invent, create, etc.) followed by a set of modifiers that make sense for the action (Conquer the dark tower RapeMurders, Master the art of stonecarving, Become the king of BronzeTowers, etc.). Dates can be assigned as either self imposed deadlines/goals (Become king of BronzeTowers by year 1028, Survive the cold until spring) or as "Action dates" (We strike the killing blow to the goblin civilization next Tuesday, We attack at dawn). Goals could either be made public (I'm campaigning to be the mayor, vote for me!), private (Don't tell anyone outside this group our plans, or I'll kill you where you stand), or personal (If my crew figures out what I plan to do, there will surely be mutiny!).
The game can be aware of these goals and set the proper mood (The election is tonight, ready the ale for a celebration!; Tomorrow, we're up against an army, and there is but 10 of us - we need to plan this out [alternatively - I need a stiff drink]; We've done it! We have a stall in every market in the kingdom!)
Quests given by other people could use this framework to randomly generate more interesting quests, as well as keep track of them in a way that makes sense.
Any thoughts, objections or suggestions are welcome, as well as lists of what categories and modifiers should be implemented. This is a pretty rough, but versatile framework that could probably encompass 90-95% of whatever goals a player might have.