Chanukah is 8 days long and begins on the 25th evening of the Jewish month of Kislev. It is a celebration of light over darkness.
A small group of men defeated one of the strongest armies in the world and drove the Greeks from the land. They reclaimed the Holy temple. When they went to light the menorah in the Temple, the discovered only one cruse of pure oil. This one day supply burned for a full 8 days until new oil could be prepared.
In our homes, we light menorahs to publicize these miracles which is why Chanukah came to be.
Chanukah customs include eating foods fried in oil -- latkes (potato pancakes) and (doughnuts). We play with the dreidel and the give Chanukah gelt, gifts of money, to children. The actual custom is to give this gelt (money) rather than toys and other gifts but some do both or give gifts alone.