This has just happened in my group and since we were all dying with laughter I'll share the situation with you (mods, if this is the wrong forum feel free to move this post).
The situation: The party is sent to investigate a frontier noble's odd behaviour and approach his castle as a snow storm begins. Unbeknowns to the party, the castle's inhabitants were all killed a few days ago - by accident, an artifact in the treasury had conjured a powerful demonic being that ran amok until, after killing everybody else, it ran into its master (chained to the dungeon wall) who banished it but still couldn't free himself.
The party, unawares of the backstory, encounters a mother/kid pair of ogres in the entrance area playing with and feeding on dead humans and horses. Both creatures are slain with little effort and just to be sure their throats are slit. Then they are dragged outside.
Searching the castle, two characters enter the lord's bedchamber and find his corpse. This triggers a ghostly apparition that proclaims they shall leave the castle alive until his murder is avenged. The apparition doesn't actually have the power to place such a geas on the party, it is just a "recorded message". But the characters know that it's technically possible and presume they are under the spell.
Naturally, they first want to find out if the supposed geas only applies to the two who entered the bedchamer, or to the whole party. The dwarf warrior is sent through the gate and the player is told by the GM he's feeling somewhat uncomfortable (because the Dwarf fears he might be under the spell). In lieu with his character (and his talents and flaws), the player decides the Dwarf won't admit to feeling uncomfortable. He refuses to go further away from the gate than the few steps he's taken, returns and claims everything is ok.
Somewhat later, lingering evil demonic power raises the two ogres outside as undead because, unlike the other corpses throughout the castle, they've been dead for only an hour or so ago. The big one returns to the stable to continue eating horses, and makes a lot of noise.
Soo... during the nightly snow storm the party returns to the dark stables and finds a big being at large which they think is papa ogre. Again, it is dispatched rather easily. In the final round of combat, the Dwarf achieves a critical against large creature with his magical mace... and rolls 97, 02 for a total of 99. The priceless magical weapon breaks. (And the ogre was out of hitpoints from the others' attacks anyways, so this particular strike didn't even matter much). The short-tempered (character flaw) Dwarfs flies into a rage over the loss, draws a morningstar and runs outside to see the smaller ogre through the gate. He runs a step or two beyond the gate, attacks the other ogre, wins initiative, rolls 01 (fumble, results inconsequential). The young ogre respons with a claw attack exceeding 250 (cut off at medium claw attack threshold) and scores a 13 C Puncture critical against AT13. Rolls a 93... which would normally mean instant death.
GM intervention decides to treat the AT13 as plate armor in this instance to give the party 9 rounds to do something; the armor is declared destroyed.
From the party's viewpoint, it has been proven beyond reasonable doubt there is a very powerful curse upon them: The two ogres outside became undead, the dwarf who went outside is blessed with phenomenal bad luck and is dying. Yep, they're strongly motivated to solve the adventure...