Perhaps we could put in some new noteblock uses. My original idea was to have certain cords played by two or more noteblocks to do certain tasks, say attract zombies or chickens, make it rain, increase/decrease mob spawn rates, trees drop more/less saplings, just random things. I'm sure we could come up with more ideas to expand on this suggestion.
There are several uses of noteblocks already. For example, if you are making a bank, you can make it so when the items arrive down a chute with water, the item goes on a wooden pressure plate, and it activates a noteblock.
Adding more uses to noteblocks.