Ramadan, one of the five pillars of Islam, is probably Islam's most important annual event. It's a month of fast, where all Muslims, except for pregnant women and travellers I believe, are not to eat or drink between dawn and sunset. Ramadan is the ninth month in the Muslim calendar, which follows the moon's phases rather than the Earth's revolutions around the sun as in the Western Gregorian calendar. The Muslim calendar year is thus 9 days shorter than the Gregorian year, and the time of Ramadan changes through the years accordingly. It's a lot easier for Muslims in Northern Africa to observe Ramadan in December when the weather is normally rather cold and rainy on the coast, than in the intense heat of summer.
Ramadan is generally observed in all Muslim countries, less so in more secular countries and urban regions.
Travel is usually not specially restricted during Ramadan, though I guess in Libya you never know... Beware of driving in the last few hours before sunset during Ramadan! People are often half-crazed from hunger and thirst and may drive like maniacs to get home to eat!
Work goes on as usual, though perhaps even less efficient.
Though it's accepted that people of non-muslim faith do not observe Ramadan, drinking and eating in the open during the day may be deemed offensive in front of people who are hungry and thirsty.
Ramadan does culminate in a big celebration. If someone invites you to their home to share in the celebrations you should certainly go.
Here's a link to learn some more: http://www.usc.edu/dept/MSA/fundamen...in/fast_1.html
[This message has been edited by OyvindSn (edited 04 September 2001).]