A place where a fertility spell has gone wrong.Kisses can lead to pregnancy, any fungus infection runs rampant, corn grows as soon as it is planted,ect.
A place where for those who sleep in it,the real life and dream world is blurred-so nightmares can be deadly.
The PC's end up in a strange world where the very rocks are made of gold and jewels.As such gold and jewels is worth very little, but the iron in their swords and belt buckles is suddenly worth a LOT.
A cave full of what appears to be gold nuggets-the nuggets are in fact radioactive and will poison whoever takes them.
A place where scratching an itch is seen as highly rude.The problem is, it's full of biting insects.
There is a place where there are living dinosaurs but in miniture.So there are foot long Tyranosaurus Rex's and four foot long Brontosauruses, for example.
A new substance is found in an out of the way area and kept very quiet. It is found to make a perfect counterfeit diamond. Only the most expert of expert appraisers would even have a hope of noticing that it is fake. Only one problem: if it gets wet it starts to slime and if it is saturated, it turns into a glob of gel.