Eid ul Adha

Eid ul Adha (10 Dhul-Hijja) - the festival of sacrifice

Find this year's date in the multifaith calendar

Animals are sacrificed and then distributed among family, friends and the poor

This is a four-day public holiday in Muslim countries.

The festival remembers the prophet Ibrahim's willingness to sacrifice his son when God ordered him to.

Ibrahim's sacrifice

God appeared in a dream to Ibrahim and told him to sacrifice his son Isma'il. Ibrahim and Isma'il set off to Mina for the sacrifice.

As they went, the devil attempted to persuade Ibrahim to disobey God and not to sacrifice his beloved son. But Ibrahim stayed true to God, and drove the devil away.

As Ibrahim prepared to kill his son God stopped him and gave him a sheep to sacrifice instead.

Celebrations

Ibrahim's complete obedience to the will of God is celebrated by Muslims each year.

Each Muslim, as they celebrate, reminds themselves of their own submission to God, and their own willingness to sacrifice anything to God's wishes.

During the festival Muslims who can afford to, sacrifice domestic animals, usually sheep, as a symbol of Ibraham's sacrifice. (British law insists that the animals must be killed in a proper slaughterhouse.)

The meat is distributed among family, friends and the poor, who each get a third share.

As with all festivals there are prayers, and also presents.
  Source      http://www.bbc.co.uk/religion/religions/islam/