One to three people leave the room (depending on how large the group is, more can leave) believing that the rest of the group are creating a dream they had the night before. This is not the case.
When the 1-3 people come back to the rest of the group, they will have to ask yes/no questions to figure out this dream. The reason they ask yes/no questions is because the rest of the group will be answering yes to the questions that end in with a vowel (Did this dream involve a slice of provolone cheese? Yes), no to the questions that end with a consonant (Was I in the dream? No) and maybe to the questions that end with the letter "Y" (Did the dream take place at Frost Valley? Maybe). The person or people asking questions have to figure out the pattern.