I inflated about 200 blue and green balloons and static clung them to the ceiling. I also hung blue and green crepe paper about 6 inches from the ceiling...this made it look like we were underwater. I drew the outline of a large ship on brown paper on a roll and taped it on the walls of the playroom...complete with circle windows as portholes and then used ziploc baggies half filled with blue water, then taped behind the brown paper. I had all different size boxes in the corners and plastic battery powered lanterns also. I recycled fish nets I had from a Luau party and used these as decorations as well. I had blue rope lights all along the perimeter of the ceiling as well. This really set the scene and the kids loved it!