Each room has a different theme: one is a huge ball pit, another is a dance room with many many disco balls on the ceiling. The green room has green balls, the red room has red and so on. The roof outside has a bubble machine that blows bubbles into the yard 24/7, and has dogs that love to play fetch. He has a book room where someone is always available to tell him a story.
To amuse myself, I placed a bowling alley in the basement, croquet, petanque, and bocci ball courts in the yard. (He has no idea what these things are- perhaps he will love them later.) His favorite part of the story is where he goes outside to the dog run and throws the ball for the dog, who fetches and drops the ball at his feet, so he can throw it again. At specific words he does sign: "dog", "ball", and he even points to his feet! It is freaking adorable. At bedtime, I'll tell him to lay his head on the pillow so he can have a story, which he does eagerly. Then he signs "please" and "ball"- meaning, "Please tell me about the House of Balls".
I have also caught him using his toys to act out scenarios (feeding his ball popper toy, making Puck his doll talk, or talking in babble to his worm or fox). He often will "read" books to himself, pointing at the pictures and narrating them with babble. His imagination is firing on all cylinders and I wish I knew what was going on in there!