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
Today is the first of the two Rosh Chodesh ("Head of the Month") days for the month of Tevet (when a month has 30 days, both the last day of the month and the first day of the following month serve as the following month's Rosh Chodesh).
The Yaaleh V'yavo prayer is added to the Amidah and to Grace After Meals, and the additional Musaf prayer is said (when Rosh Chodesh is Shabbat, special additions are made to the Shabbat Musaf). Because it is also Chanukah today, the "full" Hallel (Psalms 113-118) is recited (and not the "partial Hallel" said on the Rosh Chodesh days of other months).
Many have the custom to mark Rosh Chodesh with a festive meal and reduced work activity. The latter custom is prevalent amongst women, who have a special affinity with Rosh Chodesh -- the month being the feminine aspect of the Jewish Calendar.
Links: The 29th Day; The Lunar Files
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 seven lights. (In the Jewish calendar, the day begins at nightfall; this evening, then, commences the 7th 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?
When the Mighty Waters cover your head, suffocating the soul and the flame that burnt inside . . .
When raging torrents of confusion drag you away in their current, ripping you from your hold on Life . . .
Look deeper. Beyond the soul.
For the soul itself, as well as the flame it holds, are rooted in a serene G‑dly World of Emanation, a world of quietness and sublime harmony.
But the turbulence of this world is rooted even beyond that, stemming from a World of Confusion, of light unbounded and untamed, before the orderly emanation of defined being, “and the world was confused and void, with darkness over the face of the deep.”
So you must dig deeper than those roots, to find the coals from which the flame arose and the flint rock from which the spark was struck. Deeper, until you reach the primordial essence of the soul, beyond Emanation, beyond Light—even beyond the unbounded light of pre-creation. Where there is nothing but the seminal thought which inspired all that is and was and will come to be.
And what was that thought? It was the thought of you here and now, in your struggle with this world, and the delicious taste of your victory.
And, since in that thought there is no past and future, there, in that thought, you have already won.
Now you must make it happen.