This is Shirakiku's ramune drink -- a soda imported from Japan that Mrs. HowChow first found at Ginza of Tokyo.
Ramune is a cool little experience. The soda is soda -- sweet and interesting enough in flavors like lychee, pineapple, and melon. But it's a cool experience because there is no bottle cap. The bottle is topped with a marble and a plastic lid. You punch down the marble with a plunger that is packaged inside. The marble rattles around a bit. As you drink, it rolls around a small chamber and get covered in carbonation bubbles. (You won't really swallow the marble because it can't fit out the top.)
Fun little diversion. Cute for a party. Great for a Japanese theme -- or if you know anyone who loves Japanese comics. I may stock some for the next visit from my nephews, although I don't know if they drink fruit sodas.
You can buy the ramune sodas -- along with sushi and Japanese steakhouse cuisine -- at Ginza of Tokyo on Johns Hopkins Road near La Palapa Too. I also found them in a half-dozen flavors in the H Mart in Catonsville. Ask for them, or look in the displays between the two lines of frozen food.
(Update: Dzoey says below that Sushi King and other Japanese restaurants sell ramune.)
For more information about ramune, check out Asian Aisle, a blog that Sheri turned me onto over the summer. Great photos of the bottles and the marble, and Asian Aisle profiles lots of items that you could find at Asian grocery stores. If you want to see the bottle, you can check out YouTube. If you're a juvenile delinquent, go back to YouTube to see how to melt the bottle cap to free the marble.