Yom Kippur

"...In the seventh month, on the tenth day of the month, you shall afflict your souls, and you shall not do any work ... For on that day he shall provide atonement for you to cleanse you from all your sins before the L-RD." -Leviticus 16:29-30

Judaism 101: Yom Kippur (http://www.jewfaq.org/holiday4.htm)

sunset October 1, 2006 - nightfall October 2, 2006 ~ Yom Kippur is a complete, 25-hour fast beginning before sunset on the evening before Yom Kippur and ending after nightfall on the day of Yom Kippur. Yom Kippur is probably the most important holiday of the Jewish year. Many Jews who do not observe any other Jewish custom will refrain from work, fast and/or attend synagogue services on this day.

The name "Yom Kippur" means "Day of Atonement," and that pretty much explains what the holiday is. It is a day set aside to "afflict the soul," to atone for the sins of the past year. Yom Kippur atones only for sins between man and God, not for sins against another person.

Yom Kippur is a complete Sabbath; no work can be performed on that day. It is well-known that you are supposed to refrain from eating and drinking (even water) on Yom Kippur.