Gamelan Jawa

Gamelan is a musical ensemble with a lot of instruments involved, such as Gong, xylophones, bamboo flutes, drums, etc, sometimes there is also singer (called: sinden, has to be a female (s)).
All of the instruments aren't interchangeably and will have to be played together to form an ochestra-like.
Gamelans existed in Indonesia before Hindu-Budhist period, this is a native art from Java.
The songs of gamelan is normally consisting of repetitive rythm and if there is a sinden who sing with it, normally thelyrics comes from an old javanese poem/folksongs.
There are slightly different rythm and instrument from Javanese, Sundanese or Balinese Gamelan.

http://en.wikipedia.org/wiki/Gamelan

all instrument pictures and descriptions below are taken from thsi website: http://www.joglosemar.co.id/gamelan.html