One of my recent finds during a trip to Daiso was this ice ball mold:
It makes three spheres of ice which are about 6 cm (2.25 inches) in diameter. I love them. They keep a glass of water very cold (but they can roll forward and hit your front teeth, very bad!).
The spheres are about the same size as the Muji ice ball molds I bought earlier this year:
If your freezer is nice and cold the spheres can come out with a lot of it being clear ice, it’s pretty. I have to find an event during which I can serve punch and float these in it. I have not yet tried to freeze something inside of the balls but intend to do that very soon. See more pictures of these here in my Flickr.
Aside: the Muji molds are listed as small and I’d really like to see what a large size might be.
Also, the Muji UK has the puzzle cookie cutter set back in stock.