You're probably already familiar with the story, but it's simple enough if you're not. A cursed magical item that grants whatever wish you make with it, but never in the way you want, and always in a way you regret. The classic example is wishing for money, only to receive it as a settlement after the death of a loved one. If you had such an item, would you tempt fate? What wish would you make?
As far as posting games go, this one's pretty straightforward. Look at the wish made by the person above you, and decide the twisted, ironic way their wish is fulfilled. Then make a wish of your own, and see how the next person in the thread grants it. Two quick rules that will make things more entertaining:
No lawyering. If you really wanted, your wish could be pages and pages long, trying to ensure that it's granted exactly how you want it. But that's no fun. Wish makers, try to keep your wish to a sentence, at most two.
No giant meteors. So many wishes, from "I wish I was happy for the rest of my life" to "I wish to end child poverty" to "I wish I never had to see my ex again" can be granted with the same rote response: "a giant meteor hits the earth and kills everyone lol". This works but is a bit uninspired. Wish granters, try to come up with something more tailored to the wish, rather than a giant meteor (or something similar).
I'll start us off with something well intentioned but probably easy to twist. Have fun!