A powerful wizard and his apprentice (also powerful) are after an artifact which is carefully guarded (by various traps, magics, etc) in a labyrinth. Put in there years ago by various leaders and since forgotten. They cannot think of a brute force way to get it, but they are clever enough to have figured out some loopholes which will allow a low-level bunch of adventurers with various characteristics (tailor to your players, one obstacle per player or combination of players) to get in safely and escape with the artifact.
The wizard cooks up a long term plan (perhaps he is an elf) to obtain such a party of adventurers. This plan is subtle and tricky as that is the style of this wizard (he likes to manipulate and deceive people, like a game). He has his apprentice disguise himself as an old storyteller/bard who takes a liking to a young pc or npc and tells stories of the PC/NPC's grandfather who stopped a great evil by sacrificing himself, sealing the evil and himself into a labyrinth (yes THE labyrinth). The grandfather was lost with his family sword and more importly an amulet which signified the family's power and destiny as heroes of the realm. Various stories of the grandfather, sword, and amulet should convince the PC/NPC to go after this stuff.
The storyteller also tells of the PC/NPC's family talent for dowsing, and helps him cut a dowsing rod and casts various covert magics to make the character believe he has such power. Eventually he replaces the dowsing rod with an identical duplicate which is set up to find the other characters who are needed to get the artifact back (yes, the party). The character recruits or finds the party and they go and get the amulet back.
The wizard and apprentice appear at the exit from the labyrinth and reveal the hoax (part of the fun), demanding the amulet. The apprentice is either given or takes the amulet for the wizard, then gets a greedy look in his eyes and makes to put it on. The wizard vaporizes the apprentice and takes the amulet.
You might want to put some sort of treasure in this labyrinth so the party won't be too pissed that they have been deceived. The wizard invites the characters to join in his "games" (see below).
If they decline, he does various things to convince them to comply. If that fails, he cooks up another complicated deception to get them to join in. He will not force them to join, unless he feels that he has sufficiently deceived them.
He cooks up a quest designed to bring the party eventually to a spot at which the wizard has planted a "Caiman Bush". The Caiman stone and the Indigo flu are complete fiction. The party will not find anybody else who knows about these even if they ask around. The Caiman Bush is an elaborate magic item, which will teleport the party into the Wizard's lair. The wizard will then inform them that the only exit from his lair is to win the game.
The game is versus another party which has been in suspended animation waiting for opponents. (Losers of the game are suspended and continue to play until they win, whereupon they are released). Make the game whatever you wish.
You should maybe allow the party to acquire some limited magic items from the game, so they won't be quite so pissed to have been manipulated.