1. Official: Rains Of Castamere
George R.R. Martin's universe is a fully fleshed out feudal society.
That includes oral histories conveyed in song. Without the ability to read or write, ballads were how most of the populace remembered the past and expressed their emotions. Martin created verses for almost a dozen songs but most haven't made it into the show, leaving it up to talented fans to breathe life into them. And these are just the ones with lyrics. There are dozens and dozens of mentioned songs just waiting to be polished up and sold for $.99 on iTunes.