Prophet Muhammad's birthday

http://islam.about.com/od/otherdays/a/milad.htm

In the Islamic calendar, the 12th day of Rabi-al-Awwal marks the birthday of the Prophet Muhammad (peace be upon him).

There is a difference of opinion about whether the Milad Un-Nabi should be a time of celebration. There is evidence that the Prophet, his Companions, and the early followers after them did not celebrate or otherwise observe his birthday. On the contrary, Muhammad was careful to warn his people not to imitate other faiths, whose followers elevated their prophets and added to the religion what was not in the original teachings.

Those who disagree claim that although not practiced in the early years of Islam, the remembrance of the Prophet's birthday is a "good innovation." They see it as a time to read the Qur'an, and remember the life, teachings, and example of the Prophet Muhammad.

*NOTE* - Shi`is recognize his birthday being on the 18th day of the same lunar month.

"And your face that shines like the sun
Has been unveiled on the finest night
The night of your birth bestowed happiness on religion
And splendor on its day
The day the daughter of Wahb succeeded in getting
Of prestige what other women never succeeded in attaining
She came to her people with a pregnancy
Superior than that of the Blessed Virgin Mary before her
A birth that resulted for the disbelievers
In nothing but woes and epidemics
And the glad tidings of rejoicers came one after another
That the chosen one was born and happiness was a must."
- al-Barzanji