Approximately 40 singers form the Sunday Choir, a group that performs a wide range of choral literature for the Sunday services of Memorial Church in Harvard Yard. In recognition of their commitment, all members of this group are paid. Auditions for positions in the Sunday Choir are held early in the Fall Term. The choir attracts singers who like a challenge, singing a wide variety of music at a professional standard with a weekly performance deadline. This group performs in the annual Christmas Carol services and spring concert, and collaborates with other musical groups, both on and off campus. The Sunday Choir also undertakes both international and domestic tours.