I am a Christian but I have many Jewish friends who are celebrating Hanukkah. It is a holiday celebration that lasts for eight (8) days and it has been observed for more than 2000 years. The word Hanukkah means "dedication". But it is also known as the Festival of Lights.
If you would like to know more about the holiday, My Jewish Learning published an excellent article: The History of Hanukkah.