Islands of War is a TL4 fantasy setting involving quite a number of islands in an arctic archipelago. Each island is heated volcanically to different temperatures, creating a plethora of environments.
The political atmosphere is highly charged, with many of the island kingdoms constantly on the brink of war. This should give the PCs a chance to affect things, for good or ill.
Here are some adventures from this setting that I'd suggest for a Dungeon Fantasy game (some re-tooling might be needed if you're not using Islands of War, but it shouldn't be too difficult):
Clearing the Gnomish Mines
The PCs are called in by a gnome clan to help deal with a sticky situation involving giant beetle people killing their miners.
Snow Day
While traveling, the PCs stumble across the Snow King, a snow-man demon, and his army of Demon Ninja Snowmen!
The Mercenaries (This will probably require more re-tooling than the others)
The PCs are called in to search for a load of missing people. After a following a few leads, they get hypnotized into paying for busting up a bar they didn't bust up...
The Syndicate Wants You, Dead
The PCs meet an enchanter who's just been paid a visit by the Enchanter's Syndicate for selling magic items too cheaply. He's "accidentally" broken all the fingers in his hand.
Foresight
The PCs meet a poor woman that's being tormented by Death himself.
Beginner's Luck (Not quite finished with this one, but it should be usable)
The PCs are hired to help a group of Rogue Modron adventurers to be better adventurers. All goes well except for the simple milk-run they're supposed to nurse-maid them through isn't quite so simple...
Return of the Nine
The adventure hook will require significant re-tooling, but the meat of the adventure should be usable. Anyway, a cave that used to belong to a group of nine Medusa witches has suddenly become a source of trouble, once more. No one sent in so far has come out, so the PCs are sent in to handle the situation.
Please note that I didn't use the GURPS magic system to build these adventures. I rolled my own magic system using a spells as powers approach, so spell casters will look a little odd to you, since all their spells are equipment (spell-book pages), instead of skills. Just poke around in the wiki a bit. It should become clear what's going on. Try the
Rules page.