Calpis, known as Calpico in USA, is a "refreshingly sweet and tangy" non carbonated soft drink. It comes in a variety of flavors (personally tried maybe four) and I always enjoy it. Some people that I have shown to, like Ms. Noodle, has not shown an interest to it because of it's color and sometimes the taste. The original seen here has a color that looks to be of skim milk. Not to pleasing when you look at it I guess. I enjoy it and the original has a unique flavor to it that sorta taste of milk but has a strong acidic flavor that of Orange Juice sometimes.
It was first marketed in July 7th, 1919 during pre-war Japan and was popular because of the non-need to refrigeration. It's polka dot packaging refers to the Milky Way and Tanabata Day which falls on July 7th.
I recommend trying it once as it is a well known drink in Japan and maybe give the many more flavors a chance. You can find it in America labeled as Calpico, Calpis pronounced here in the states sounds like "cow piss" which is probably a reason while they wanted a new name for marketing.
You can find it as a regular sized bottle or this 1.5 litter bottle which I paid $2.99 for.
By Mr. Tea
info from Wikipedia