Many versions of this game exist.
Host vs. Guest
Pick two sides, randomly or let them self-organize. You want the sides to number roughly the same.
If no intrinsic Host/Guest role exists in your situation, flip a coin to determine which role goes to which side.
Pick a team name, corresponding to a natural element of creation…animals, weather, landscape, etc.
Guests knock on the imaginary door.
Hosts open it, and begin the harangue, starting Round 1.
First Hosts speak, Guests listen. Then they trade.
Same, raising the eloquence stakes.
Hosts concede, Guests listen. Guests accept, Hosts listen.
Goal for Host: Play down the Host’s home, hospitality, wealth. Play up the Guest’s importance, fineness, and too-high of station for the Host’s home. Convince the Guests that they won’t feel satisfied with the Host’s home, only capitulating in Round 3 if the Guests persist.
Goal for Guest: Play down the Guest’s station, importance, fineness. Play up the Host’s. Convince the Host team that the Guest team will feel satisfied with the Host’s home, only capitulating in Round 3 if the Hosts won’t back down.
“Mentors” – Pick one Speaker and one Coach for each side. The Speaker only says what the Coach whispers into the Speaker’s ear.
Extra Rounds – Raise the stakes by adding rounds. Additional option; give each side its own secret round to “take a fall in”.
Styles – Pick a style for the sides to emulate. “Rhetorical”, “Musical”, “Rhyming”, etc.