Guests could dress in Victorian best. Signs are written so the words are flipped backwards. The icing is inside the cake, not outside. Streamers are on the floor. Paste balloons on the stage upside down, with their strings attached to the ceiling.
Tablecloths are under the table.
Girls ask boys to dance. Brave guys wear dresses. On the wall, there is a mural showing dogs walking their people and prisoners arresting their jailors. Flowers on the tables are stem side up. You get the idea.