This improv game is in the following improv game categories:
Split the group in 2. Half of the players leave the room while you explain the game to the others: we are going to make stories in pairs. We will tell the other players that we came up with a great story, and they have to guess it. The catch is that they can only ask yes/no questions, and we do not really have a story. We will answer `no` to every question that starts with a vowel or with a conjugation of `to be` (or some other criterion). In addition, after having answered 2 consecutive No`s we will always answer a yes.
Let the other players back in and pair them up with the others. Each couple starts guessing the story, unknowingly creating a story as they go. Continue till they get it.