originally from Boing Boing Gadgets:

One of my favorite treats at an Asian grocery store is Ramune. Ramune is a soda with Japanese origins (there’s aTaiwanese version as well) that comes in a variety of sugary-sweet flavors. But the cool thing about Ramune isn’t the taste; it’s the container. Bottles of the soda are sealed up with a marble. To open them, you have to force the marble down into the bottle, where it gets captured in a small chamber within. Pop it in hard and it makes a fizzy mess; which of course can be part of the appeal of drinking it. While the bottle may appear novel, once again it’s in fact an old technologythat just happens to feel delightfully modern.

The bottle is a Codd Stopper, invented by soda magnate Hiram Codd (of the Camberwell Coddses, not those low born mother-scratching Devonshire Coddses) and patented in 1873. The idea is that the bottle uses internal pressure from carbonation to force the marble up against the rubber stopper at the lip, sealing your tasty beverage inside. 

These bottles were not popular in the US but apparently remain popular in Asia. Something to look for next time I am in a Asian foods store. The first few minutes of this video show a kid opening a bottle of Ramune: