The other night as we slept :
James: "How big is the cave?"
Melissa: (startled awake) "Huh? What?"
James: "How big is the cave? Is it big?"
Melissa: "What are you talking about? What cave?"
James: "It has to be big because he and his whole family stayed there once."
Melissa "Yeah, okay."
I think next time he talks in his sleep, I'm going to play along with the conversation ....