Rather than presenting a choice or wish to the user, you present a success. The next user must come up with a good news and bad news option for each scenario you present to the user. Rather than trying to fruitlessly explain it (I'm not all that good at explaining things) I'm just going to show you.

For example:

User 1: I marry Rainbow Dash

User 2: Good News: You have a cute new wife.

Bad News: All the RD lovers want you dead and end up killing you.

I help Applejack build a barn.

User 3: Good News: Applejack has a brand spankin' new barn.

Bad News: The barn collapses after a few days and you're too tired to build a barn.

Myself and Rarity make a dress!

And so on. Is that explained enough for you? Then let's begin.

I'll start myself and as usual, the first person to reply in the comments gets to give me the good news and the bad news. They must then post a scenario in that format and then the next user must give their good news and bad news. Then we carry on and on. Sound simple enough, right?

I build a Rainbow Dash shrine.