Festival of Offerings
From Tardis Wiki, the free Doctor Who reference
The Festival of Offerings was a millennial ceremony on Akhaten. It was a huge event, much like Pancake Tuesday, and all the species from the local system gathered to watch it.
During the ceremony, the Queen of Years would sing the Long Song to the Mummy to feed the Old God, or "Grandfather," and keep him asleep. Then the Queen would be sacrificed to him by the Vigil. (TV: The Rings of Akhaten)