Have I told you about this kid in my class? When he is finished with anything... writing his name, coloring a picture, gluing his letter sort, he holds up his work and at top volume he screams, "TA-DA!" If you don't acknowledge is ta-da immediately, then the "TA-DA!" gets progressively louder and closer together. I discovered this when I tried the politely-ignore-approach.
I very much appreciate his excitement and ta-daness about finishing a task... I think we all have a bit of that in us, but really, I hope the verbal expression of it is just a phase.