Here are some musical tools on the internet to explore creatively:
Chrome Music Lab has a variety of tools for music making
Blob Opera a goofy tool that visualizes four part harmony
Bongo Cat a tool that turns your computer keyboard into a variety of instruments
Space Drum an online tool that turns your computer keyboard into metal pan drums
Music Grid explore building a song using this grid format
Incredibox must be opened with safari browser (not chrome, it won't work), there are lots of free tools to explore with the web version for creating beats