We often play with rain-sticks at baby classes and the babies sometimes drop them on themselves and get hurt, so I had a hunt around and found these brilliant rainstick balls and got one for Ethan.  He absolutely loves it and can hold onto it easily and throw it around, and is mesmerised by the sound it makes.  He's getting better at sitting up everyday and I think this will be even more fun when he can sit and roll the ball.