I put up some party balloons and a present pile. Then obviously this one birthday banner (dont know where to find it, sorry). Obviously a cake, some music. And i let the family members give small gifts from their inventory for story-purpose (collectibles, mostly MySpace or snowglobes for kids, new toys, an instrument) If i want to give something bigger i put it in the childs room when it is not their and lock the door and then unlock it when it is supposed to be revealed (little bit stupid, but that is the only option i could think of)
