Songkran
Songkran is the traditional Thai new year celebration which takes place in April, although Thailand now generally uses the western calendar for determining the start of the new year.
It is still quite common to see the Thai year displayed using the traditional Thai calendar, which is Buddhist based and is 543 years ahead, Buddha (Siddhartha Gautama) having being born before Christ. So in the Western year 2000, it will already be 2543 in Thailand.
Now you will understand why many Thais are not too bothered by Y2K ( I'm only joking. Many Thai computer systems are based on western dates ).
Songkran is generally celebrated as a three day Public Holiday, with activities most intense on Songkran day itself.
Traditionally Thais sprinkle water on each other, by dipping their fingers into a bowl and then shaking them in the recipients direction. This water is usually fresh and often perfumed. Each year though the methods of delivering water become more and more outrageous, as Thais compete to go one better than the previous year.
You will encounter groups of Thais standing at the road side with hoses and buckets soaking passing cars, motorcyclists, cyclists and anyone fool hardy enough to be pedestrian.
Open trucks also roam the steets, loaded with large clay water urns, water tanks, re-cycled oil drums, buckets and water dispensing revellers.
In recent years 'Super Soaker' water guns have become a common method of high powered, accurate delivery.
On my first visit to Thailand on Songkran day, I went with some friends for a picnic / barbeque on the edge of a large stream, which had lengthy terraces of water falls. All morning long, a continuous single stream of white butterflies followed the water downstream. There must have been literally millions of them. In mid afternoon, they turned round and headed back upstream. It was absolutely amazing to see this continuous chain of butterflies pass by, with no let up for several hours.
More recently I was fascinated by the television coverage of a safron robed Buddhist monk, sitting on the floor, chanting prayers, before a large congregation of kneeling Thais. As the congregation continued to pray with their heads bowed, the monk solemly looked up, picked up a fire hose and comprehensively soaked all those assembled.
Sonkran is great fun and every one takes a good soaking in their stride. So if you go, which you should, make sure you wear clothes that you don't mind getting wet. You are also likely to get liberal doses of a white coloured paste smeared on you. Taking a set of dry clothes to change into is futile, since unless you lock yourself away, these too, will soon be soaked.
I have been advised that you can even throw water at Thai policemen during Songkran, without upsetting them. I haven't yet tried this out and take no responsibilty if this information is faulty.