Loi Krathong or Roi Krathong is perhaps the most colorful festival in Thailand. A krthong is raft, traditionally made out of Banana leaves. Thai people float away Krathong in river on the Loi Krathong day to float away their ill fortunes. This festival is also to apologize to the river goddess Ganga. The people of Thailand apologize to the river goddess for polluting the water and promise to do better during the coming years.
Loi Krathong is celebrated during the full moon day of 12th Lunar month. This is normally during mid November. This year, 2007 the Loi Krathong falls on 24th November. It is Saturday and I expect a big crowd near the banks of Choprya River with devotees gathering around to float the Krathongs. Here is a colorful video which explains everything about the Loi Krahtong fetival in Thailand.
It is believed that the Loy Krathong fetival is originated from the Indian festival Deepavali which is also celebrated almost at the same period.