
A bong or water pipe is a device that is usually used for smoking cannabis, but sometimes other herbs as well, such as salvia divinorum, tobacco, and substances such as methamphetamine or cocaine. Many countries have laws against owning drug paraphernalia; a bong being sold openly, such as at a head shop, is likely advertised as for tobacco use only, but this can vary according to location. Smoking from a bong is somewhat different from smoking from a pipe or joint (spliff). Most bongs are designed to either cool the smoke before it enters the operator's lungs, or to build up a large buffer of smoke which the user inhales quickly, or both. The word bong derives from the Thai word baung which refers to a cut off section of bamboo.
Bongs can vary greatly in their shape, materials, styles, colors, and sizes. Commonly constructed from acrylic, ceramic, or glass, bongs can also be fabricated from materials as diverse as pykrete or even from household objects or empty water bottles. Some people even make bongs out of fruits and vegetables and discard (or consume) them after use. Many bongs are regarded for their style, distinct vivid colors, or customizations such as stickers, and become a personalized signature of that particular bong owner. Some people even name their bongs. These names usually reflect pot culture or a distinction of said bong.
source taken from wikipedia.. cuzz its wicked.
http://en.wikipedia.org/wiki/Bong