Beginning of Ramadan 2012
Ramadan in 2012 will start on Friday, the 20th of July and will continue for 30 days until Saturday, the 18th of August.
Based on sightability in North America, in 2012 Ramadan will start in North America a day later - on Saturday, the 21st of July.
Note that in the Muslim calander, a holiday begins on the sunset of the previous day, so observing Muslims will celebrate Ramadan on the sunset of Thursday, the 19th of July.
Ramadan is the ninth month of the Islamic lunar calendar, and is the month of fasting for observant Muslims. Because the cycle of the lunar calendar does not match the solar calendar, the dates of Ramadan shift slightly each year. Officially, the month begins with the sighting of a new moon. This has historically been a point of contention as the timing of the moon's visibility may vary by location, but the start and end dates are now generally agreed upon based on modern understandings of the lunar calendar.
The origins of Ramadan draw significantly from the occasion of Laylat al-Qadr, frequently translated as "the Night of Power." It was on this night in 610 C.E., that Muslims believe the Quran was first revealed to the Prophet Muhammad and led the entire month to be seen as a holy time in the calendar. Observance of Ramadan is also mandated in the Quran's second chapter, verses 183-185:
O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous ... The month of Ramadhan [is that] in which was revealed the Quran, a guidance for the people and clear proofs of guidance and criterion. So whoever sights [the new moon of] the month, let him fast it.
In general, the practices of Ramadan are meant to purify oneself from thoughts and deeds which are counter to Islam. By removing material desires, one is able to focus fully on devotion and service to God. Many Muslims go beyond the physical ritual of fasting and attempt to purge themselves of impure thoughts and motivations -- anger, cursing, greed, etc. As part of this, service to the community and to those in need is a major emphasis of activity throughout the month.
The holiday of Eid ul-Fitr, which marks the end of Ramadan, takes place on the first day of the following month and celebrates the completion of the 30 days of fasting. On this day, morning prayers are followed by feasting and celebration among family and friends. Eid is a day of great thanksgiving for Muslims -- an opportunity to show their gratitude for making it through the month of fasting and a chance to share their blessings with others. The start of Ramadan shifts by approximately 11 days on the solar calendar each year. In 2012 Ramadan will begin on July 20, and Ramadan 2013 will begin on July 9.