After you get the latest version of Flash, you'll be able to play around with Instrumentation!
When playing or writing music, composers, conductors, and musicians have to decide what instruments will play what parts. They also have to decide what instruments will play in combination with other instruments. And that's what instrumentation is, deciding who plays what, with whom.
In this activity, you get to hear different instruments playing different roles. You decide what instrument should play which roles and with what other instruments.