There is a circle of people with two or three people in the middle. They are acting out a scene that the other members have chosen for them. And then at any point in their scene, the other members that are watching may call out "shoulda said" and the actor that it was called on has to say either the opposite of what he/she meant, or what they were really thinking. For example, I say "I love that dress you're wearing!" and somebody calls shoulda said on me, I could say "that dress would look much better on my pet rat". And of course the other actors in the scene will have not heard your extra comment. This is a really fun game!