Buddhist holidays

There are many holy days that people of the Buddhist community recognize. On these days Buddhists attend a local temple and offer food to the monks which will later be distributed to the poor.----Buddhist New Year
This day is celebrated for three days from the first full moon day in April. In Mahayana countries it starts in January. The day it actually occurs on depends on the background of the people.
Vesak
Buddha's Birthday is known as Vesak and is one of the major festivals of the year. It is celebrated on the first full moon day in May, but when it's a leap year it falls in June.
Asalha Puja Day
Also known as "Dhamma Day" celebrates the Buddha's first teaching on the full moon day of the 8th lunar month, approximately July.
Uposatha
This day is known as observance day, their are four holy days on the new moon, full moon, and quarter moon days every month.
Kathina Ceremony
This robe offering ceremony is held on any date within the end of the Vassa Retreat. New robes and other requisites can be offered by the laity to the monks.
Abhidhamma Day
According to Burmese tradition, this day celebrates when the Buddha went to the Tushita Heaven to teach his mother the Abhidhamma. It is celebrated on the full moon of the seventh month of the Burmese lunar year which starts in April.
Songkran
This Thai festival goes on for days during April where people clean their houses and clothes and sprinkle perfumed water on the monks, novices, and other people. On top of everybody being wet they can enjoy boat races on the river.
Loy Krathong
When the rivers and canals are full of water, this festival takes place in all parts of Thailand on the full moon night of the twelfth lunar month. Bowls made with leaves, candles, and incense sticks, are placed in the water, and represent bad luck disappearing.
The Ploughing Festival
During the half moon in May, two oxen pull a plough painted gold. Following behind them are girls dressed in white scattering rice seeds. This was to celebrate the Buddha's first moment of enlightenment.
The Elephant Festival
The Buddha used an example of a wild elephant which is harnessed to a tame one to be trained. He said that a person who is new to Buddhism should have a special relationship with an older Buddhist. This festival takes place on the third Saturday in November.
The Festival of the Tooth
In Sri Lanka there is a temple that houses a tooth relic of the Buddha. It can't be seen, but once a year there is a procession for it on the full moon in August.
Ulambana
"Ancestor Day" is celebrated from the first to the fifteenth days of the eighth lunar month. Supposedly the gates of Hell are opened on the first day and ghosts visit the world for fifteen days. People make food offerings to relieve the ghosts' sufferings.
Avalokitesvara's Birthday
This festival celebrates the Bodhisattva ideal. On the full moon day in March It represents the perfection of compassion in Mahayana traditions of Tibet and China.
----References
1. http://www.buddhanet.net/festival.htm