The forty days and nights of rainfall which covered the face of earth with water in Noah's time ended on Kislev 27 of the year 1656 from creation (2105 BCE. The flood itself lasted a full year, as related in Genesis 6-8).
Links: Chronology of the Flood; The Torah's account (Parshat Noach); The 40-Day Mikvah
On the 25th of Kislev in the year 3622 from creation, the Maccabees liberated the Holy Temple in Jerusalem, after defeating the vastly more numerous and powerful armies of the Syrian-Greek king Antiochus IV, who had tried to forcefully uproot the beliefs and practices of Judaism from the people of Israel. The victorious Jews repaired, cleansed and rededicated the Temple to the service of G-d. But all the Temple's oil had been defiled by the pagan invaders; when the Jews sought to light the Temple's menorah (candelabra), they found only one small cruse of ritually pure olive oil. Miraculously, the one-day supply burned for eight days, until new, pure oil could be obtained. In commemoration, the Sages instituted the 8-day festival of Chanukah, on which lights are kindled nightly to recall and publicize the miracle.
Link: The Story of Chanukah
Rabbi Chaim of Tchernovitz (1760-1817) was a disciple of the Maggid of Mezritch and of Rabbi Yechiel Michel of Zlotchov. He authored Be'er Mayim Chayim ("Well of Living Waters"), a commentary on Torah. Rabbi Chaim passed away on the 3rd day of Chanukah.
Two years after his arrest and liberation in 1798 (see entries for "Kislev 19" and here), Rabbi Schneur Zalman of Liadi (founder of Chabad, 1745-1812) was arrested a second time; again, the charges were that his teachings undermined the imperial authority of the Czar. His second incarceration was less severe than the first; yet Chassidim mark the anniversary of his release on the third day of Chanukah with farbrengens (Chassidic gatherings) and the study of his teachings.
According to other versions of the story, the liberation occurred on the fifth day of Chanukah. Apparently the liberation happened in two stages.
In commemoration of the miracle of Chanukah we kindle the Chanukah lights—oil lamps or candles—each evening of the eight-day festival, increasing the number of lights each evening. Tonight we kindle four lights. (In the Jewish calendar, the day begins at nightfall; this evening, then, commences the 4th day of Chanukah).
The lights—which ideally should be kindled soon after sunset—must burn for at least half an hour after nightfall. Learn more about the proper lighting time.
Links:
Text and Audio of the Menorah Blessings
Additional Chanukah observances and customs are listed below:
Special prayers of thanksgiving -- Hallel (in its full version) and V'Al HaNissim -- are added to the daily prayers and Grace After Meals on all eight days of Chanukah. Tachnun (confession of sins) and similar prayers are omitted for the duration of trhe festival.
On Chanukah we eat foods fried in oil—such as latkes (potato pancakes) and sufganiot (doughnuts) -- in commemoration of the miracle of the oil.
It is also customary to eat dairy foods in commemoration of Judith's heroic deed.
It is customary to play dreidel—a game played with a spinning top inscribed with the Hebrew letters Nun, Gimmel, Hei and Shin, which spell the phrase Nes Gadol Hayah Sham, "a great miracle happened there." (It is said that when the Greeks forbade the study of Torah, Jewish children continued the study with their teachers in caves and cellars; when the agents of the king were seen approaching, the children would hide their scrolls and start to play with spinning tops...)
Links: How to Play Dreidel
It is an age-old custom to distribute gifts of Chanukah gelt ("Chanukah money") to children on Chanukah. (It was the custom of the rebbes of Chabad-Lubavitch to give Chanukah gelt to their children and other family members on the fourth or fifth night of Chanukah; more recently, however, the Lubavitcher Rebbe encouraged the giving of Chanukah gelt every day of the festival—except for Shabbat, when handling money is forbidden.)
Links:
Why the Chanukah Gelt?
Joseph had two sons in Egypt. From their names, we learn how a human being can be successful in this world.
He named the first son Menasheh, which means to forget. Whenever Joseph called Menasheh, he remembered that this land was causing him to forget his true home and all that his father had taught him.
And so he never forgot.
He named his second son Ephraim, which means to be productive. Whenever Joseph called Ephraim, he remembered that he had a purpose to accomplish in Egypt, so that his family could eventually settle there in dignity and prosperity.
And so he was successful.
Just as the names of both sons were crucial to Joseph’s success, so too every human being must keep two memories awake at all times:
This material world is not your true place, for your soul descended into this body from a luminous, heavenly place.
And you are here for a purpose, to channel that heavenly light into this world.
Menasheh came first, but Ephraim, Jacob later told Joseph, was greater.
Because first you must remember that this is not your true place.
And only then will you remember to accomplish your true purpose, to bring this earthly world in harmony with that place from which you came.