Paper balloon (kamifusen - 紙風船 or かみふうせん)

Kamifusen is a paper balloon. The word 'kami' means paper and 'fusen' balloon. Children play with it just by passing each other the ball in the air. As the balloon is very light and can't break anything, the kamifusen is an ideal indoor game.

http://store.hiromipaper.com/kamifusenballoons.aspx