InventorSpot give their list of the Top Ten Weird and Bizarre Japanese Drinks as proof that Japan is at the forefront of beverage ingenuity. Do you dream of cucumber-flavored Pepsi? They've got it! How about salad flavored water? Got that too! Kids want to join in on the beer-drinking fun? Just give them a frosty bottle of non-alcoholic Kidsbeer!
If you have a local Japanese supermarket ("browsing supermarkets" is one of my major pastimes, at least) be on the lookout for "interesting drinks that probably wouldn't survive in the US market." There are loads of them. Check out Dan's photos of bizarre Japanese beverages for inspiration.