What is the tea ceremony?
Called chado or sado, the Zen Buddhist-influenced Japanese tea ceremony is the ritual of preparing and serving powdered green tea in the presence of an audience. Tea ceremony has been a part of Japanese culture since the 14th century. It is nearly always practiced in a dedicated teahouse, and participants sit on tatami mats as the host or hostess uses the tea utensils to whisk the powdered green tea and hot water into a frothy beverage. The host or hostess of the ceremony engages in creating an environment of aesthetic, intellectual and physical enjoyment for the guests and in turn, guests focus on the beauty of the objects—tea utensils, symbols of nature—that surround them. The objective of such a ceremony follows the concept of Zen Buddhism, which is to focus on the moment and one’s surroundings. Currently, many different schools practice and teach tea ceremony throughout Japan.

http://web-japan.org/museum/tea/teat.html