Today at the All Saints' feast day Mass we had an organist, but no cantor. So he simply left off playing the liturgical parts that required a cantor, such as the Alleluia verse.
Felicity didn't find this quite satisfactory, so while the priest slowly processed with the gospel book, she sang out:
Toot Toot Chugga Chugga Big Red Car
I didn't dare look around to see if anyone else was stifling laughter.