I ran a game once with an annoying antagonist that liked to play cards...while the PC's were trying to figure out how to thwart her (and without putting the "hostages" in harm), she would play a unique game of cards with them, and as just mentioned, depending on outcomes (who played what, who won, etc.) they would fight things based off of a list I had made...this would usually involve extraplanar as well as interplanar travel. It turns out the cards were not magical, but the table they were playing on was, which is why the toughness of the creatures were altered based on how many bets had been made (this caused large objects to be hurled at me when it was figured out). Something like that can be dangerous to throw at characters, though, with seemingly random effects...I wonder what would have happened if someone had thrown a Bag of Holding down as a bet...
Oh, here's another one...a ring, seemingly enchanted, with some sort of advanced magic cast on it that lower level Identify-ish spells wrongly determine as good things (pluses to something or another)...has a sub-effect related to the effect that psychically determines who the wearer has had contact with in the past week with strong emotional ties (usually antagonist NPC's and party members, somtimes others with varying interesting results)...Another sub-effect, more a catalyst than anything, is the ring's ability to chain contingency off of the spell or the spell effect (or similiar) Dispell to occur within 250 square feet of the wearer of the ring. Once the latter sub-effect occured, unless the Dispell area-effected or specifically targeted the ring by high level magic, the main effect would come into play, being that there are actually several, several of these rings scattered about the multiverses, and any time a ring wearer's ring uses the main effect, all current ringwearers and their emotionally-tied friends/enemies/etc all switch places in group with another said group. Unless Dispell is eventually cast by VERY high level magic, the rings are never destroyed, but if high-enough level magic is used, the ring's group of confused members (only the group who's ring was directly affected by the Dispell) are "teleported" back to their original positions (though time has passed, possibly causing danger to them) in their home plane and the ring is randomly "teleported" to another location in the Omniverse. Also, it had a quirk...if Wish or the effects of a Wish or similiar spell/effect (including Djinn abilities and including objects conjured by a Wish or similiar spell of effect) came within 50 square feet of the ring, the main effects were automatically set off. If anybody wants to use this or alter it and use it, feel free, it's public...keep in mind, as is, the ring teleports everyone the character was emotionally-tied to within the past week, including NPCs they may have come in contact with in other realms...we had an experience with my PC's finally getting the ring dispelled, but a very powerful and very antagonistic NPC they had briefly encountered (but had grown to hate because of local friendly NPCs' testimonies against the tyranical dictator) got permanently teleported back to their plane and wreaked havoc for a few sessions. It also has weird varying effects when certain characters born with innate psychic abilities wear the ring or high level Empathy/similiar spells/effects occur within some close proximity of the ringwearer as they put the ring on.
Sorry for the long post. Don't smite me, please.
