Bukkit/CraftBukkit — pull request #789 by obnoxint (2012-06-10 15:43:05+00:00)
Title: Added NotePlayEvent - Adresses BUKKIT-1779

This event is being called when a player interacts with a note block or the note block is being powered by a redstone current.

Discussion and demonstration:
http://forums.bukkit.org/threads/i-implemented-a-noteplayevent.79921/