Not very entertaining. Here's why:
There was one problem with this:
It wasn't very "playable". I'd hit a key, a note would play, but then I'd have to wait a bit to play another. Here's my suggestions:
1.) Make it so that I can play as many notes as I want, when I want. Add in a feature that stops all sounds in case I want silence.
2.) Or, make a sequencer, similiar to the game "Punk-O-Matic".