Yeah, definitely an odd one: Cruiscín Lán. It's an Irish Gaelic drinking song, an ode to a little brown jug which is always full!
My Dad was a Trad fiddler, and this song has a simple repetitive rhythm if you slow it down a bit. Both my kids demanded it when they were sleepy, but luckily Irish is a language few Americans understand, so we didn't get funny looks if I sang it softly in public.
I was visiting a cousin once in England, and one of my Dad's sisters was there. The cousin's baby was getting fussy, and I picked him up and started singing it, in Irish as I always do. My Aunt was nearly ROTFL, that I'd sing a drinking song to put a baby to sleep!