well I sing...a lot. So I sing what ever pops into my head.

Alphabet/twinkle twinkle/baa baa black sheep (well they're all the same tune anyway), It's a long way to Tipperary, Sadie the Cleaning Lady, Down by the station, My old man's a dustman, I've been working on the railway, catch a falling star....what ever nursery rhyme pops up next.
Sadly I can usually get through my whole (very long) repertoire before the little rat will actually go to sleep these days....