Tonight is the first night of Hanuka (חנוכה). Hanuka is the best known of the Jewish holidays, at least in the US, it is therefore assumed to be the most (or at least, one of the most) important. It is not. Its prominence in the US is due solely to its proximity to Christmas, giving Americans an excuse to call December the "Holiday Season". (Personally, I have always found this patronizing, we all know what holiday the "Holiday Season" is really about. Rather like a parent making a big deal about winning the consolation prize.) In fact, Hanuka is one of the least important Jewish holidays. It is not one of the seven holidays of the Tora (Pesah, Shvi`i shel Pesah, Shavu`ot, Rosh Hashana, Yom Kipur, Sukot, Simhat Tora), it's a far younger holiday, added in historic times, to celebrate the victory of the Jews over the Seleucid Greeks, and the rebirth of the Jewish state in 165 BCE.
Hanuka in Israel is fun precisely because it's not so serious. If you don't have children, you probably won't feel it much at all. But children love it. In most families, every member of the household lights a hanukiya (חנוכיה) - the special candelabra made for celebrating the holiday. A kosher (fit) hanukiya has eight candlesticks in a row, a the same level (actually, to be more precise, they must be arranged such that when viewed from the front, no two candles are overlapping). A ninth candlestick must be either not at the same level, or not in line with the others - this candle is called the shamash (שמש). The Hanuka candles are specifically the eight candles in a row - the shamash is emphatically not a Hanuka candle, which is why it must be distinguished from the others. Its presence is required because of a singular restriction on the use of Hanuka candles, namely that you can't. It is forbidden to use the Hanuka candles, it is permitted only to enjoy them. When lighting the candles we say the following:
הנרות הללו אנו
מדליקים, על הניסים, ועל הנפלאות
ועל התשועות, ועל המלחמות שעשית לאבותינו
בימים ההם בזמן הזה, על ידי כוהניך הקדושים
וכל שמונת ימי חנוכה, הנרות הללו קודש הם
ואין לנו רשות להשתמש בהם
אלא
לראותם בלבד
כדי להודות ולהלל לשמך הגדול
על ניסיך, ועל נפלאותיך, ועל ישועותיך
Hanerot halalu anu madliqim, `al hanisim, v`al hanifla'ot
V`al hat'shu`ot v`al hamilhamot she`asita l'avoteynu
Bayamim hahem bizman haze, `al y'dey kohaneykha haq'doshim
V'khol shmonat y'mey hanuka,hanerot halalu qodesh hem
V'eyn lanu r'shut l'hishtamesh bahem
Ele lir'otam bilvad
K'dey l'hodot ulhalel l'shimkha hagadol
`Al niseykha, v`al nifl'oteykha, v`al y'shu`oteykha
These candles we are lighting, for the miracles, and for the wonders
And for the victories, and for the battles that you made for our forefathers
In those days at this time, by means of your holy priests
And all of the eight days of Hanuka, these candles are holy
And we don't have permission to use them
But only to look at them
In order to thank and praise your great name
For your miracles, and for your wonders, and for your victory
"Your holy priests" refers to the priestly family, the Hashmona'im, who led the rebellion against the Seleucids, and the passage as a whole is meant to remind us not to use the candles. The purpose of the shamash is to be the candle that we use (i.e. if the other candles weren't lit, the light of shamash would be enough), if we need to.
During Hanuka, we insert the following words into every prayer, and the blessing after every meal. A short history of the day:
ועל הנסים ועל הפורקן ועל הגבורות ועל התשועות
ועל הנפלאות ועל
הנחמות ועל המלחמות
שעשית לאבותינו בימים ההם בזמן הזה
בימי מתתיהו בן יוחנן כהן גדול חשמונאי ובניו
כשעמדה מלכות יון הרשעה
על עמך ישראל להשכיחם תורתך
ולהעבירם מחוקי רצונך
ואתה ברחמיך
הרבים עמדת להם בעת צרתם
רבת את ריבם דנת את דינם נקמת את נקמתם
מסרת גבורים ביד
חלשים ורבים ביד מעטים וטמאים ביד טהורים
ורשעים ביד צדיקים וזדים ביד עוסקי תורתך
ולך עשית שם גדול וקדוש
בעולמך
ולעמך ישראל עשית תשועה גדולה ופורקן כהיום הזה
ואחר כך
באו בניך לדביר ביתך ופינו את היכלך וטיהרו את מקדשך
והדליקו נרות
בחצרות קודשך וקבעו שמונת ימי חנוכה אלו
להודות ולהלל לשמך הגדול
V`al hanisim v`al hapurkan v`al hagvurot v`al hatshu`ot
V`al
hanifla'ot v`al hanehamot v`al hamilhamot
She`asita l'avoteynu
bayamim hahem bazman haze
Bimey Matityahu ben Yohanan kohen gadol Hashmonay
uvanav
K'she`amda malkhut Yavan harsha`a
`al `amkha Yisra'el l'hashkiham toratekha
Ulha`aviram mehuqey
r'sonkha
V'ata b'rahameyhka harabim `amadta lahem b`et saratam
Ravta et rivam, danta
et dinam, naqamta et niqmatam
Masarta giborim biyad halashim, v'rabim biyad
m`atim v't'me'im biyad t'horim
V'r'sha`im biyad sadiqim, v'zedim biyad `osqey toratekha
Ulkha `asita shem gadol v'qadosh b`olamekha
Ul`amkha Yisra'el `asita t'shu`a g'dola ufurqan
k'hayom haze
V'ahar kakh ba'u baneykha lidvir beytekha ufinu et heykhalekha v'tiharu et
miqdashekha
V'hidliqu nerot b'hasrot qodshekha v'qav`u shmonat y'mey Hanuka
elu
L'hodot ulhalel l'shimkha hagadol
For the miracles, and for the salvation and for the mighty deeds
and for the victories
And for the wonders and for the consolations and for the battles
That you made for our forefathers in those days at this time
In the days of Matthew son of John the high priest, the
Hasmonean, and his sons
When the wicked kingdom of Greece stood over your people Israel to make them forget your Tora
And to make them transgress the statues of your will
And you in your great compassion stood with them at the time of their troubles
Disputed their disputes judged their judgments, avenged their
vengence
Delivered the strong at the hand of the weak, the many at the hand of the few, the defiled at the hand of the pure
And the wicked at the hand of the righteous, and the wanton at the hand of those who busy themselves with your Tora
And for yourself you made a great and holy name in your world
And for your people Israel you made a great
victory and salvation as this day
And afterwards your children came to the sanctuary of your house and cleansed your Temple and purified your holy site
And lit the candles In the courtyards of your holiness and established these eight
days of Hanuka
To thank and to praise your great name