Why even bother with a dream? "As soon as your hand touches the chair, everyone in the room is flung into a parallel dimension, each of your consciousnesses replacing the consciousness of the previous host, Quantum Leap-style. You are all sitting in a high school cafeteria on folding metal chairs...."
Then find a way to tell the players that you all need to somehow get the low-INT barbarian inhabiting Karen's body elected PTA president before their consciousnesses can be returned to their original bodies.