It is a challenge to create an easy creative environment online that isn't deadly boring at the same time. I have stumbled across several musicking gadgets that seem to do the job perfectly well and are so much fun too!
Tonematrix by aM laboratory. It is so addictive, and so easy.
Pianola game. By piano-makers site. Great way to engage the customers!
SonicWire Sculptor takes a 3D approach.