Sukkot.

Sukkot is a Biblical holiday celebrated on the 15th day of the month of Tishrei (late September to late October). It is one of the three biblically mandated festivals Shalosh regalim on which Jews were commanded to make a pilgrimage to the Temple in Jerusalem.The sukkah walls can be constructed of any material (wood, canvas, aluminum siding, sheets). The walls can be free-standing or include the sides of a building or porch. The roof must be of organic material, known as s'chach, such as leafy branches, bamboo or palm fronds. It is customary to decorate the interior of the sukkah with hanging decorations, the Seven Species.During the Intermediate days of Sukkot, gatherings of music and dance, known as Simchat Beit HaShoeivah, take place. This commemorates the Water Libation Ceremony in which water was carried up the Jerusalem pilgrim road from the Pool of Siloam to the Temple in Jerusalem.The holiday immediately following Sukkot is known as Shemini Atzeret . Shemini Atzeret is viewed as a separate holiday. In the Diaspora a second additional holiday, Simchat Torah (lit. "Joy of the Torah") is celebrated. In the Land of Israel, Simchat Torah is celebrated on Shemini Atzeret. On Shemini Atzeret the sukkah is left and meals are eaten inside the house. Outside of Israel, many eat in the sukkah without making the blessing. The sukkah is not used on Simchat Torah.