Tomorrow (Sept 20, 2009) moslems in Indonesia as are those throughout the world are going to celebrate Eid ul Fitr or Lebaran as it is popularly called here.
Lebaran is the largest and most festive holiday here, probably comparable to Christmas in many other parts of the world. (Christmas is also a big holiday here but not as big as Eid ul Fitr.)
One of the most important traditions of the Lebaran is that people would visit their parents, families, and relatives to ask for their forgiveness and improve ties. For those who live in the cities, this means traveling back to their hometowns and villages. Done by a huge number of people at about the same time, the travel imposes a huge logistical burden on the country's public transportation system which, I must admit, is not in a very good shape. Train tickets would normally be sold out a month ahead of the holiday, so are bus, airline, and ship tickets.
Those who have cars would travel with them. Others would just try about anything to get to their destinations, including riding motorbikes and other means of transportation like trucks and bajaj (a three-weeler motorbike taxi).