First of all, i want to wish all my Chinese reader who celebrate Chinese new year Gong Xi Fa Chai and prosperous tiger year 2010 ahead. Traditionally, Red envelopes or red packets (Cantonese: lai sze or lai see) ; (Mandarin: 'hóng bāo' ); Hokkien: 'ang pow' ( âng-pau); Hakka: 'fung bao'; are passed out during the Chinese New Year's celebrations, from married couples or the elderly to unmarried juniors. It is also common for adults or young couples to give red packets to children. 
In Vietnam, red envelopes are called lì xì (similar to the Cantonese pronunciation "lai see") or, in some cases, phong bao mừng tuổi (happy new age envelope). In Thailand and Malaysia, they are known as ang pow or ang pao for Philippines (the pronunciation of the Chinese characters for "red envelope" in the Hokkien/Fukien dialect) or tae ea among the Chinese-Thai. In Myanmar (Burma), the Burmese Chinese refer to them as an-pao (Burmese: ), and South Korea's envelopes are called "sae bae ton" and the envelopes are white, not red. In Japan, there is a monetary gift called otoshidama but white envelopes are used with the name of the receiver written on its obverse.
There are no clear literary sources from which to trace the origin of the red envelope tradition. In China, during the Qing Dynasty, the elderly would thread coins with a red string. The money was called yāsuì qián, meaning "money warding off evil spirits", and was believed to protect the elderly from sickness and death. The yāsuì qián was replaced by red envelopes when printing presses became more common. Red envelopes are also referred to as yāsuì qián.
Red envelopes are mainly presented at social and family gatherings such as weddings or on holidays such as the Lunar New Year. The red color of the envelope symbolizes good luck and is supposed to ward off evil spirits. During Lunar New Year, red envelopes are typically given to the unmarried by the married. The amount of money is usually a single note to avoid heavy coins, and to make it difficult to judge the amount inside before opening. It is traditional to put brand new notes inside red envelopes.
The amount of money contained in the envelope usually ends with an even digit, in accordance with Chinese beliefs; for instance 88 and 168 are both lucky numbers, as odd-numbered money gifts are traditionally associated with funerals. But there is a widespread tradition that money should not be given in fours, or the number four should not appear in the amount, as the pronunciation of the word "four" resembles that of the word "death", and it signifies bad luck for many Chinese (See Numbers in Chinese culture). At weddings, the amount offered is usually intended to cover the cost of the attendees as well as a goodwill to the newly weds.
Wish everyone:新春佳节，祝你虎年大吉大利，大显身手，虎气冲天！
(Xīnchūn jiājié, zhù nǐ hǔnián dàjí dàlì, dàxiănshēnshŏu, hǔqìchōngtiān).
Wish you good luck in the Chinese New Year of the Tiger. Take the spotlight and fully show yourself.
Source: Wikipedia.
