Play instruments, get better, NPCs react to your skill dynamically, many new songs, lots of easter eggs, simple implementation. A compact, yet powerful Bard Gameplay Overhaul.
I've only just started my career as a bard, but playing the flute badly any time I want to is the most fun I've had in Skyrim for years. I don't know how much more there is to this mod, but I'm already sure it's among the best.