I get quite a few hits on this website on my cake posts, so I thought I'd give a few extra tips for making this cake. The nice thing is that it doesn't require any fancy cake decorating skills because I made all the toppers from construction paper. I made the triangles for the banner and the circles the week before, using rainbow colored construction paper, and some white printer paper. For the banner, I folded the construction paper in half and cut the triangles along the folded edge so that they could open up and then I stuck some floss in the folds with a little rubber cement.
I also taped the backside of the banner triangles so that the grease from the cake wouldn't soak through and make it look ugly. Once the cake was frosted, I dabbed a little frosting on the backs of the triangles(the sides with the tape) and then stuck it on the cake and loosely tied the ends of the floss together. For the circles on top of the cake, I used rubber cement and toothpicks for the shorter ones in front and rubber cement and kabob sticks for the taller ones, though I cut off a couple of inches on the kabob sticks so they weren't super long.