Don't know if this is the best place to discuss the idea, but...
I've had this plot kicking around in my head for the longest time, and maybe it'd make a good NaNoRenO project. It's actually been written already. Almost. Here's what I mean:
The idea is to take the story of Gilbert and Sullivan's comic opera Ruddigore
, and to make it non-comic. You see, every event throughout the course of the story has enormous tragic potential - which is always used for comic effect by introducing incongruous frivolities. The only real exception to this pattern is the ending - which is such hilarious nonsense that it has no tragic potential whatsoever. So the idea is to remove the frivolities, focus on the darker side of every situation, and replace the ending with one entirely more devious (to which end I have something in mind).
For those of you unfamiliar with Ruddigore
(probably most of you; I hadn't heard of it until last year), here's the basic premise:
A young man (Robin) in a small town is in love with a young woman. The feeling is mutual, but neither is willing to admit it. When the young man finally summons the courage for a proposal,
it is revealed that he is the long-lost older brother of the local baronet (Sir Despard Murgatroyd), and should therefore be the baronet himself; he is therefore forced to take on this role. There is a long-standing curse upon the line of baronets that mandates that he commit some awful misdeed every day, and so the baronet is always deeply feared and reviled. Of course the young woman calls off the marriage. And if he refuses to commit his daily crime, Robin will be tortured to death by the spirits of his ancestors.
The curse itself has a tragic backstory that is introduced at the beginning of the opera: an ancient baronet tortured a witch to death, and the curse is her revenge.
Of course there are further complications in the story, such as Robin's rivalry with the brother he has from his adoptive family (who eventually
brings in the Royal Navy to attack Robin
if I recall correctly).
And here's a number from the opera, sung by Despard (the protagonist's younger brother): http://www.youtube.com/watch?v=tkkxPeI-wIo
That's Vincent Price playing Despard, by the way.
Something like this could probably be told with whatever stock castle and seaside village backgrounds I can find and a few appropriate sprites.