Today is the first day of Ramadan, which celebrates the revelation of the Koran to the Prophet Muhammad. It is a time of fasting and reflection for Muslims throughout the world. This year there is some sadness as Ramadan starts. There is continuing violence in Syria, and a very bleak situation in Somalia (caution, article is heart-breaking). Nonetheless, Muslims throughout the world are participating in fasting and reflection.
Here is a handy guide from the Washington Post for non-Muslims about Ramadan. Mideast Post has a nice piece on what to do if you attend an iftar, which is the evening meal that breaks the daily Ramadan Fast.
Here is a servicey video on the history of Ramadan if you want to know more.