A semi-clear liquid, looking more like beer than anything else, sold as a soft-drink. Guarana is an extract of some plant. It is sold profusely here in Brazil. And it is GOOOOD stuff. Guarana has many of the properties of caffeine but more of a kick and less side-effects. Combine that with a handful of sugar and some fizzy water and you have yourself a very good drink. Oh, it tastes great too which helps. Why mention this drink? Well, it has been my sustinance for the past six days of conference. When the days grow long and the sleep keeps getting less and less, there is nothing like a large bottle of Guarana to put the "zing" back into life. Two bottles and you not only have the "zing" but there is a "buzz" starting to happen as well. After three, there is no stopping you and it is possible to do things without tiring. I label this one the "zoom" factor. So every day I have been "zinging" and "buzzing" around the place with the help of my friendly Guarana. Not too much "zooming", but the term does come from real life experience. Cold and fresh, it is a classical Brazilian drink. If you find it in your country then grab a bottle and check it out. Great stuff.