I want to preface this by stating that I feel this question best belongs on this board. If I have made a mistake, I apologize in advance and will delete the post right away.

I'm about to start up a game set in Forgotten Realms, specifically in the North-ish region. The basic plot is that a quiet and unimportant town has recently discovered a vast source of wealth. They need to decide what they're going to do regarding this wealth and the sudden interest the rest of the world now has in them.

My question is, What is a good source of wealth for them to discover? My initial thought was a seam of gold, but it feels so blah. Does anybody have any input on what a good source of suddenly discovered wealth would be for this town? I'm trying to shy away from mineral wealth, but it seems to be the best option.

Feel free to steal this idea.  I ran a game once where a town unearthed a forgotten dragon horde and had to deal with the sudden interest of the surrounding nations and organizations.  There's all sorts of angles to take, but I'll list out a brief brainstorm for you:

• Surrounding nations start trying to claim that they are responsible for the town and have an escalating border dispute.  All kinds of opportunities for social interactions, intrigue, and nefarious plots.
• Word gets around to other dragons, who show up to lay their own claims to the horde.  Maybe some of them claim to be the progeny of the horde's original owner.  How do they settle it without killing each other?  Do they end up resorting to killing each other?
• Maybe the horde is being depleted, and then the dragon that put together the horde shows up and is enraged.  Where has he been and why has he returned?  Maybe he's some sort of Underdark dragon?  Or maybe his wings were destroyed somehow, and he's forced to live underground.
• The town has to inventory and move the horde somehow, so maybe that's how the heroes get involved initially as guards?  A good hook may be that they can pick any one item from the horde in return for getting the whole thing moved to town, and they end up fighting off hordes of bandits?

Those are my thoughts, and you can feel free to steal/use/repurpose/ignore any or all of them.

There are always options other than mineral wealth. They could have found ancient artifacts that are incredibly powerful magical items and ancient knowledge. They could have discovered a garden full of rare herbs that have the power to reduce age or be used for incredibly powerful magical rituals. They could even find something like a herd of animals long though to be extinct or gone, now having magical or pseudo-magical properties.

In reply to Ginkgo Bear (msg # 1):

I recommend that you just posit that it's true that the city has a source of wealth, and then work with your players to come up with it. Players will come up with answers that a) interest them and b) are plausible to them, meaning that there's much less effort required to draw the players in and convince them. Also, since the players at least partially came up with the idea, they'll have some incentive to help it make sense within the larger world, or at least not question that it does make sense.

That said:

A new kind of an old mineral. In Neal Stephenson's books there's a form of gold that is identical to normal gold, but is slightly more dense and has mystical properties. Maybe there's a type of silver that is better than usual at harming silver-sensitive creatures, or it's a mineral that it turns out some nuisance monster is allergic to. For instance, Eberron has byeshk, which harms a certain type of monster better than anything else.

Certain magical reagents. In 4th Edition, there are consumable treasure items that can augment certain spell types. These are things like a special sand that gives a bonus to spells that daze or slow, or a kind of exploding nut that augments fire spells. This town has a source for those.

Drugs are always an option. They start as "medicine" of course, until they get really popular. The population of the city doesn't use them, of course, just exports them, which is lucrative, but draws the ire of certain groups. Think of poppy farmers as an example. Or maybe the drug is a necessary aspect of the world economy. Think "Dune."

They export a skill taught only to their people. Maybe it's only taught by a certain house, or it's got a hereditary nature to it, so that you have to marry in to learn it, or maybe only your kids can learn it. It makes a lot of money for the city, but it's also a bit of a curse, as the population leaks away, and is sometimes kidnapped. The Dragonmarked houses of Eberron are bit like this: they're rich because literally only they and their members (usually family members, aside from a lucky few, who they make sure to snatch up) can do what they do.

A certain food. There's a reason why lots of popular real-world foods are named for a specific region or town.

Run these ideas past your players, and then go with their idea, which might not be any one of these, but will be perfectly tailored for your game.

They could raise a breed of sheep with wool that is suddenly all the rage, like merino or angora. Or they could have developed a new dye or dye method that the nouveau riche crave because it's different and hard to get and not covered by the sumptuary laws yet.

Maybe the three alchemists of the town created a new tincture that controls gout without nauseating side effects and have set up a factory to produce it in quantity. Or the armorer who has lived there since the last war has developed a new method of hardening steel or a lighter form of steel (or has invented steel) and set up a foundry to make it in bulk.

Maybe a wandering saint or sage has settled here and established a shrine or school, drawing pilgrims or students.

Maybe someone in the village has discovered that the sap of nearby trees that only grow in this region can be used to waterproof cloaks and even seal the seams of boats much better than other methods.

Maybe the local vintner has discovered how to distill a potent beverage from the turnips that grow here so abundantly.

As an addition to the "wondrous plant" idea(s) mentioned previously; you can always use the rediscovery of a plant.

Image if a plant had been thought to be extinct, and it had a marvelous property (not something too effective like anti-aging), such as: curing fevers or other low-end ailments.

You would have alchemists and herbalists rushing-in to abscond with the plant(s), some groups rushing to destroy it, merchants trying to steal it to sell it for themselves; and now you have a cool, but, very ephemeral antagonist: Greed.  It's not that the people are "evil", it's that general greed entices bad behavior.

You could have dozens of non-combat, and even investigative encounters to RP!

Entrance to a legendary and long forgotten dungeon.

Deepspawn.
http://forgottenrealms.wikia.com/wiki/Deepspawn
A Lovecraftian horror that devours other creatures, then spawns multiple obedient clones of them. Thing is, it's actually kind of useful. In setting lore, an old dwarf empire used one to manufacture clone armies. In Skullport, there's a business that uses captive deepspawn to manufacture monsters to order, for use as guards, minions, dungeon-stuffers, or gladiatorial combat. So, if they're not scrupulous, your folk could discover a deepspawn in a cave under the town and use it to churn out creatures and sell them into slavery, manufacture armies, etc. (like Star Wars: Attack of the Clones). Only they'll need some new creatures to feed to the deepspawn to get a more varied supply... Or they could just throw in some cows or rothe (local buffalo-like animals) in, and get a steady stream back for sale as food (like the Order of the Stick comic with goblins selling hydra heads). It's a Realms-specific monster too.

And this is the Forgotten Realms, so looting the treasure, lore, and magic of fallen empires is a typical industry. The town could discover a local ruin where adventurers can pull out a lot of treasure, magic items, even lost books and scrolls and other works, which various groups will pay handsomely for.

 One of the most potentially dangerous but interesting could be a Portal. The Realms has a few of the things that are permanent, point-to-point transit systems built by old mages and they're a license to print money if they go anywhere interesting or near anywhere interesting. For bonus points, put three or four portals in one massive cavern and watch as every economic and military power in the Realms perks its ears...

 ...bonus points for having no idea what's on the other side of any of them, making them instant adventure-holes for any of the players who are particularly exotic (but from somewhere in the Realms proper).

 http://forgottenrealms.wikia.com/wiki/Portal

Oh yes, portals, Faerun is riddled with them:
http://archive.wizards.com/default.asp?x=dnd/archfr/pg
A safe portal-route will slash travel times for merchants, allowing them to cross the continent in seconds. The town can get rich on trade, tolls, and services.

A plot-hook for a town in the North discovering a portal in its midst has already been done, even:
http://archive.wizards.com/dnd...asp?x=fr/pg20020220a
If they can deal with the hobgoblins of the Gray Forest on the other side, the folk of Longsaddle could open a trade-route between Waterdeep and the Silver Marches with Impiltur and the Vast, completely circumventing all the mercantile powers of the Moonsea, Western Heartlands, and Sea of Fallen Stars – and destroying the portal would be in their best interests.

I think I'm going to put all of this together, somehow, with an idea I had some time ago. The characters have a small town they call home. They discover an old portal/fey road, is a ring of megalithic stones protected by a Portal guardian. The characters wake up the Guardian, who sends them on a quest. Success lets the characters access the circle of portals. The characters can go through any portal, but to make the return trip they need to finish whatever quest/favor assigned by the portal guardian on the other side. This way, one town can be host and home to a variety of characters (and a variety of levels). Each stone goes to a specific area, which allows for a variety of locales to explore while still having a home to return to.

The only problem, as I see it, is that I want this to be a game focusing primarily on writing. The rules and mechanics are a distant focus. Maybe seventy five percent freeform, twenty five percent everything else. Characters would be given a situation and it's up to them to write it out and keep things moving, naturally with my input.

In reply to Ginkgo Bear (msg # 11):

Why is that a problem?

So make the focus of the quests not based around physical conflict or immediate danger.  Instead of exploring the lost ruins for an ancient relic, they're making contact with the last remnants of a decaying civilization and learning what they can before it fades from memory.  Instead of getting captured by a dictatorial empire, they are treated as ambassadors who are looking to re-establish ancient and forgotten trade routes between worlds and must navigate the political landscape of cloak and dagger with aplomb.  Instead of becoming mired in a nation's war for survival against their bitter enemies, they become involved in a nation's racial conflict where their morals are put to the test and they must make choices that will have lasting effects.  And each of these can have an appropriately vague quest line.  "Rescue the lost knowledge of Mbamba" or "Reap the benefits of forgotten connections" or "End the feud which has raged for two hundred years" or something that doesn't necessarily imply that one answer would be better than another.

Think about the show Stargate for how things may work.  They're explorers first, diplomats second, and survivors/warriors last.

I was getting a Stargate vibe too.