I nearly typed that as "What did you sing at school, Dad?" My father died many years ago, but I expect his answer would be "Much the same as you did at junior school" - lots of hymns, folk songs and popular/ traditional stuff. You know the sort of thing, to be found in books like 'Songs That Will Live Forever', a 1930s compilation (by Maurice Jacobson) that an elderly lady passed on to me the best part of half a century ago: The Ash Grove, Frere Jacques, What Shall We Do With the Drunken Sailor, John Peel...except that by great good luck there was some much more unexpected stuff as well.
I remember the arrival of an inspirational music teacher, Russell Farman, at my school when I was about nine. He gathered up a choir by the painless method of getting us all to sing something in unison and walking round listening to us, played us lots of Vaughan Williams' music, and was keen on early music too. The Christmas carol repertoire got an injection of pieces like Lullay Myn Liking, The Angel Gabriel, and A Virgin Unspotted, though the first year infants continued to sing Away in a Manger excruciatingly flat every year, but that's traditional, after all.
I was actually prompted to think about all this because in the last few days I've heard two pieces on the radio that I remember singing at Grammar School, and haven't heard since. The first was Thomas Campion's Never Weather-Beaten Sail (1613), the second was Bach's Magnificat (Et Exultavit Spiritus Meus) - and anyone would be forgiven for thinking that whoever chose those for school use was out of their tiny mind, especially the Bach, which was for class singing (boggle).
In fact I enjoyed singing the Campion, and it's remained a favourite piece of mine. It was for the house choirs to sing in competition at our school's annual arts fest, so no more than about ten or twelve voices to each group and it's quite simple, despite being a bit esoteric (not to say a tad morbid, to modern ears). The Bach, on the other hand, is showy, taxing, and for solo female voice - couldn't be less appropriate, really. I listened to it being professionally performed in astonished silence that we had managed to get even part of the way through it!