File under neat stuff I didn't know:
This Sunday is the final Sunday in the Epiphany Season. [...]
It has been the custom of the Church for many, many years to sing hymn 54 "Alleluia! Song of Gladness" as the Recessional on the Last Sunday after the Epiphany. (The hymn dates from the 11th century.) This will be the last time the word "Alleluia" is said or sung in the Church until Easter Day. In Medieval times, it was the custom to write the word "Alleluia" on a piece of vellum or papyrus, put it in a small coffin and bury it in the church yard, where it stayed until the coffin was dug up and opened on Easter morning.
(Via email from Rev. Robert Bowman, Interim Rector at St. Luke's)