The Festival of the Bells is the Fraggles' Winter Solstice celebration. Fraggle legend says that the Rock slows down as the Solstice approaches. At this time, the Great Bell (which lies at the heart of the Rock) must ring in order for the Rock to keep moving for another year. In order to wake the Great Bell, all the Fraggles in the Rock ring their own, smaller bells. The bell-ringing ceremony is the centrepiece of the Festival.
Other Festival of the Bells traditions include the dance of the Weebabeast and the giving of gifts (frequently the same pebble over and over).