Children’s Hospital Boston, whether you’re there for your own kid or not, always makes for an emotional visit. Miracles performed and dreams dashed, all under the same roof. So Children’s goes to great lengths to fill its corridors with laughter. And this brings us to the beloved Bippity Boppity Balls. The Bippity Bop, as it’s known, is an “audiokinetic” sculpture that has elicited awe and wonder in the lobby ever since artist George Rhoads built it for Children’s in 1997.