the thing about birthday cakes is they have no calories, she says. no matter how many slices, how many mouthfuls of sponge or buttercream frosting or chocolate glaze: still not a single calorie, or fat gram, and no carbohydrates either.

so what's in birthday cakes? i ask, being the scientific one.

happy vitamins, she says and stares hard at me, vitamins that make you feel good inside. some of them are for laughter, some for smiles, others for good sleep or even for remembering cool jokes when you need to impress someone.

really? i say.

really, she says.