Joshua gets a super-massive (don't drop it!) no-prize for bringing this Scientific American article about recent black hole discoveries to our attention. Turns out there's a black hole out there that's been "singing" a single note (a B-flat 57 octaves below natural C) for at least the past 2.5 billion years.
Yeah, I know, sound in space. Puzzled me too. Seems like the thing is nested in a gas cloud, maybe that's how it transmits sound.