Goalball

I just got my very own goalball ball today :-) The ball is an official goalball ball. It weighs 1.25 kg. What's special about this ball is the fact that it's not inflated. It's made of hard rubber and it's hollow - that's because there are bells inside. When the ball rolls on the ground (the ball must not bounce, but must be rolled on the ground - kind of like a bowling ball), the bells jingle and the players can locate the ball by sound.
Here are two links to sites where you can read more about goalball:
Goalball (Wikipedia)
Goalball UK