Kathina

KATHINA
The Kathina festival, which originated 2,500 years ago, celebrates the largest alms-giving ceremony of the Buddhist year.
It occurs at the end of the Vassa, or monsoon, period, in October and November. During the Vassa period, normally nomadic Buddhist monks will have remained in one place for three months, and the Kathina celebration marks the time for them to move on. The festival also celebrates the offerings of cloth that are given to the monks upon their leaving by the lay people.
The offering can take place up to one month following the end of the Vassa period, from 19th October to 16 November, and is celebrated by buddhists of the Theravada tradition.
HISTORY
According to the scriptures, a group of thirty monks were journeying together with the intention of spending the Vassa period with the Lord Buddha, but the Vassa began before they reached their destination and so they had to stop.

The monks were upset that they were unable to be with Buddha, who later heard of their plight. As a reward Buddha gave some cloth, which he had acquired as a gift from one of the lay community, to the monks and told them to sew a robe and then bestow it upon one of their company. The Buddha said that there was nothing as uplifting as generosity and sharing, and so the monks set about sewing a new set of robes. They used a frame, called a Kathina, on which to spread the cloth as they were making it.
THE FESTIVAL
Lay supporters now continue this tradition at the end of the Vassa. The cloth giving is a gift of the followers of Buddhism, and therefore no monk is allowed to request or organise the festival.
The cloth, according to Buddha, must be offered to the whole Sangha community, who will then decide among themselves who receives the gift.
Buddhist families take joy in offering cloth to their teachers. About three metres of cloth is all that is needed, but very often other items are offered as well. On the day of the festival, people begin to arrive at the monastery and begin by sharing a meal. At about 1 o clock, they will formally offer the cloth and other gifts.
Two monks will be presented with the cloth on behalf of the whole Sangha community. These monks will then formally announce the member of the community who will receive the cloth once it has been made up.
The monks will spend much of the night preparing and cutting the cloth, and finally sewing it together to form a robe.
The formal Sangha act (Sangha Kamma) of presenting the cloth to the chosen monk may take place much later in the evening, when it is ceremonially presented to the nominated monk.

Source from http://www.bbc.co.uk/religion