There are dozens of great recordings of traditional and modern gamelan music for those who would like to learn more about this fascinating musical tradition. I recommend any of the albums released by Celestial Harmonies in their "Music of Bali" seriesor, if you can find them, the gamelan recordings on the King Record Co. label, out of Japan.
Favorite recordings also include those from Gamelan Pacifica and Gamelan Son of Lion, as well as Ngaio Gamelan by David Parsons, and Cudamani. On the softer side, Dreaming In Gamelan by Bell Brennan and Andy McNeill is also wonderful.
Books
The best book I've found so far is Michael Tenzer's Balinese Music, from Periplus Editions. Also worth checking out is Amazon's list of books about gamelan.
Websites
American Gamelan Institute
"Gamelan music of all kinds, in Indonesia and around the world, is supported and documented by the American Gamelan Institute, an organization devoted to publishing, recording, distributing, and making available information on all aspects of Indonesian performing arts and their international counterparts. AGI was founded in 1981 to support all those involved in the many traditions of gamelan, and to gather and share information in many forms."
Gamelan On Wikipedia
"A gamelan is a musical ensemble from Indonesia, typically from the islands of Bali or Java. The term refers more to the set of instruments than to the players of those instruments. A gamelan is a set of instruments as a distinct entity, built and tuned to stay together. The word gamelan comes from the Javanese word gamels, meaning "to strike or hammer", and the suffix an, which makes the root a collective noun."
Gamelan Sekar Jaya
"Gamelan Sekar Jaya (GSJ) is a sixty-member company of musicians and dancers, based in the San Francisco Bay Area, specializing in the performing arts of Bali. Founded in 1979, Gamelan Sekar Jaya has performed throughout California, the US, and Bali—in venues ranging from New York’s Symphony Space to remote village squares in Bali. "
Gamelan Groups in the USA
"There are more than 100 gamelan groups in the United States. A gamelan is a musical ensemble from Indonesia, typically from the islands of Bali or Java, featuring a variety of instruments such as metallophones, xylophones, drums and gongs; bamboo flutes, bowed and plucked strings."
International Gamelan Directories
"These are directories of currently active gamelan groups and groups performing related arts who can be contacted via the internet. Our lists include some contacts in Indonesia, where gamelan are plentiful but internet connectivity is not, as well as many groups outside of Indonesia in countries where the situation is reversed."
Harry Partch's Instruments
"By 1969, the year he recorded 'Delusion of the Fury,' Harry Partch had designed 27 new instruments, all to be played on stage at the same time in a spatial ritual theater. These instruments were made to be beautiful in sound, vision, and 'magical purpose.'" On this site you can play the Partch instruments, listen to Partch explain each instrument, and hear musical examples.