Ramadan is the ninth month of the Islamic lunar calendar. This is the month during which Muslims’ holy book the Quran was revealed; Hassan the second Shi’ite Imam was born; the Prophet’s son-in-law Ali was murdered; a conclusive battle at Badr was won; and Muslims are expected to fast. One of the main rituals of Islam, fasting is obligatory for all Muslims except the sick, pregnant women and some travelers. In all cases once health is restored or traveling has ended, these missing days should be made up by fasting (for the same number of days).
The practice is observed for the whole month and ends with the celebration ‘Fitr’.
Such self-control is believed to benefit the individuals by elevating their spiritual nature or energy and is symbolic of an inner purification of the character. The believers must have good intentions (niyyat) in their mind when fasting.
This intention must be pure and the ritual should be performed for the love of God only, not for the sake of earthly gains or even the reward of paradise. Special acts of piety, such as the recitation of the entire Quran (one-thirtieth each night of the month) and prayers specific to Ramadan are performed privately or communally at the mosques. Alms are given to the needy and charitable people will provide free meals at sunset when “ending the fast meals” are consumed.
 The end of Ramadan is celebrated on the first day of the month of Shawwal with a great feast named Id-i Fitr. The feat of breaking the fast calls for a solemn prayer, Salat al-Id.
 Most people will attend their local mosques for communal prayers. The last feast or iftari is more elaborate and is quite often joined by family, friends and neighbors. On this day the statutory alms marking the end of the fast (zakat al-fitr) are given. The more prosperous families give to the poor a prescribed quantity of the customary food of the area as an act of piety.
In the past the occasion was celebrated with grandeur with the local rulers participating and people joyfully attending the occasion.

Revelation of Holy Quran
The last 10 days are especially important because the Quran was revealed in this month at the ‘Night of Power’ (lailat al-qadr). The Quran is the foundation of Islam and the unadulterated word of God; it is the Divine Word par excellence. Each single verse of it is called ayat “sign" or miracle because the Prophet brought forth these verses as Divine signs when his adversaries asked him for a miracle attesting to his prophecy. According to the Quran, the “Night of Power” is better than a thousand months put together. Some people will retreat into prayers during these last ten days. These are called days of i-tikaf or retreat and it ends with the festival Id-i Fitr.
The night is usually celebrated on one of the last odd nights in Ramadan. The Shiites of Iran celebrate the night from 19th to the 21st of Ramadan.
It is said that prayers on this night are worth a thousand prayers on any other night. Also the period coincides with Imam Ali’s assassination and his subsequent death on the 21st.  For this reason, Ramadan is more a month of mourning for the Shiites than celebration. The three nights from the stabbing to his death are known as the nights of Revival (shab i aheya) and are mourned privately or communally. People stay up all night reciting special prayers and at times will hold the Quran on their head while praying loudly or crying.

Martyrdom of Imam Ali
Martyrdom is very important in Iranian Shiite’s ideology and Imam Ali’s assassination and his death are mourned intensely by the devout Shiites. According to their account, when the holy prophet died, leadership of the community was passed on to Ali, his cousin and son-in-law. Muhammad had raised Ali as a child. He was the first male convert and fought bravely for the faith. He was a constant aide and when the prophet withdrew from Mecca under the cover of night to escape assassination in 622, Ali remained behind as a decoy in Muhammad’s bed. Ali was assassinated while praying in the mosque of Kufa. The details of his martyrdom like those of his son Husayn have become legends remembered and mourned by Shiites ever since.
The preachers in the mosques enlighten the events of the three nights and Ali’s foreknowledge of his death.
The stabbing during prostration is symbolically very significant. Muslim daily prayer ‘namaz’ includes different positioning while praying. Ali was stabbed during the second prostration. One meaning given to the prostration is that the first refers to "from dust we are created"; the worshiper then sits back, resting upon his haunches, which represents life. The second prostration refers to "and to dust we return"; the concluding act of rising to one’s feet represents the final judgment. Ali is stabbed during the second prostration and putting the dust of the mihrab on his wound symbolizes his return to dust and acceptance of his fate and God’s will. The preachers during this part of the story recite the verse from the Quran about man being from dust. In the end, how Ali’s children mourned his death is passionately described and all participants are encouraged to cry loudly and express extreme sorrow.                                                     (Source: cultureofiran.com)