One I've had rolling around in my brain for awhile. For some reason, Dr. Horrible has gotten ideas churning in my head for RPG adventuring. Kinda goes along with the points of light concept of 4e, but doesn't necessarily have to use it.
The king/prince/ruler of the realm has done a pretty decent job, but he's in over his head. He's an old adventuring buddy of yours, ambitious, well-meaning, but beleagured. Said realm is in a strategic position. Lots of factions would like to see it fall, both within and without. He's managing to cope so far.
Until the earthquakes. Until smoke began rising from picturesque Mount Tessarisq, a mountain smack in the center of the realm. Yep, agree the druids. It's a dormant volcano not so much so. Big surprise there, as none of the legends speak of it that way–and the realm is rife with legends that involve Mount Tessarisq. Fortunately these days it's a mostly uninhabited area of the realm. Well, all except for the village of smiths and artificers who have been instrumental in assisting the flagging fortunes of the realm.
Your job: Figure out what to do. Move the villagers to safety? Find out why the sudden eruption? Why do some of the villagers have a memory of a legend about an angry magma-related goddess that no one outside that village has?
He really needs your help. So do all the people of the realm. No pressure. Except under the earth, apparently…