My Cleo used to love the tin foil ball when she was little. I think because it sparkles as it catches the light. Also it's light and easy to carry and because it's uneven, not smooth like a ball, they can pick it up easily with their teeth. (eeuw - can you imagine doing that yourself, the thought makes me squirm, like fingernails down a blackboard) We haven't tried the foil ball for ages, maybe we should resurrect that game. Currently she likes the feathers and streamer things on a stick. Colette likes little toy mice, the tiny ones.