The Gawai Dayak festival is celebrated every year on the 1st of June, at the end of the harvest season, to worship the Lord Sempulang Gana. On this day, the Ibans get together to celebrate, often visiting each other. The Iban traditional dance, the ngajat, is performed accompanied by the taboh and gendang, the Ibans' traditional music.
Source: http://en.wikipedia.org/wiki/iban
