the Festival of Lights is an eight-day Jewish holiday commemorating the rededication of the Holy Temple (the Second Temple) in Jerusalem at the time of the Maccabean Revolt of the 2nd century BCE.
Hanukkah is observed for eight nights, starting on the 25th day of Kislev according to the Hebrew calendar, which may occur at any time from late November to late December in the Gregorian calendar, says Wikipedia.
The festival is observed by the kindling of the lights of a unique candelabrum, the nine-branched Menorah or Hanukiah, one additional light on each night of the holiday, progressing to eight on the final night. The typical Menorah consists of 9 branches.
Hanukkah is celebrated by a series of rituals that are performed every day throughout the 8-day holiday, some are family-based and others communal. There are special additions to the daily prayer service, and a section is added to the blessing after meals.
Hanukkah is not a "Sabbath-like" holiday, and there is no obligation to refrain from activities that are forbidden on the Sabbath. Adherents go to work as usual, but may leave early in order to be home to kindle the lights at nightfall. Many families exchange gifts each night, and fried foods are eaten.