When I was a junior school, I usually played either "Poor Mary", "Oranges And Lemons" or "The Farmer Wants A Wife" but I can only remember the lyrics to "Poor Mary" so here goes

Poor Mary sits a weeping/ A weeping/ A weeping/ Poor Mary sits a weeping/ On a bright summer's day

Oh tell me what you're weeping for/ You're weeping for/ You're weeping for/ Tell me what you're weeping for/ On a bright summer's day

I'm weeping for a playmate/ A playmate/ A playmate/ I'm weeping for a playmate/ On a bright summer's day

Well stand you up and choose one/ And choose one/ And choose one/ Well stand you up and choose one/ On a bright summer's day

At least I think those are the lyrics, it's a looooooong time since I've played it.