Among the many holidays in the Balinese 210-day calender, the most prominent are undoubtedly those of Galungan and Kuningan, the former on the Wednesday of the Dungulan week and the latter on the Saturday on the Kuningan week. Due to their frequency - roughly once every seven Gregorion months - these festival are not celebrated as national holidays, but don't try to do anything beetween Penampahan Galungan (the day for the slaughter of the pigs as a form of defeated evil that precede Galungan) and Manis Galungan, the day following it, or on the Friday preceding Kuningan, everything is closed. People go back to their village of origin to presents offerings to their ancestors and village temples.
Unlike most Balinese festival which celebrate the particular anniversary of a temple, and are therefore scattered across the calender, Galungan and Kuningan are all - island holidays, everywhere, "Penjor - a tall, curved bamboo pole decorated with coconut leaves with an offering at the base which symbolizes the mountain and the mountain itself is the symbol of the universe with aim of erecting penjors at Galungan is to show devotion to God in His manifestation as Hyang Giri Pati (the God of the mountain)." are along the street in front of Balinese house, temples are all dressed up, with batik and white or yellow cloth wrapped around their individual shrines as a sign that they are "occupied", meaning the gods are visiting their descendants. The ritual involved is a reminder of the strong ancestor's cult aspect of the Hindu - Balinese religion. When it took root in Bali, Hinduism integrated elemants of ancestral beliefs and natural animism into its corpus, the rationale being that everyting and every belief can be interpreted as "ray" or a manifestation of the "Ultimate Sun" of Surya(Siwa).
The ancestors do not come before being properly "invited". They are expected to come on the Sugihan Jawa day when one makes offerings for the welfare of the world. The visit of the ancestors is expected to last until Kuningan, the shrines are then undressed and the temples return to quietness, waiting for another festival.
So, if you happen to be in Bali for one of these two festival, either Nyepi or Galungan, don't miss a visit the villages.