So, I knew this would be a stretch for them to get into, but I had to try!

The book ends as it began, and the violinist exits.
So, go forth, ye, and giveth this book a try!
Here's what we did:
1. Gather kiddos at a good time of the day when they are up for creative thinking... not a cranky time of day like I do sometimes.
When music is played, we can see colors and pictures in our minds depending on what the music sounds like.
3. Go through the book pointing to the pictures, imagining what the music is like, singing what it might be like, describing if it looks loud or soft, fast or slow, happy or sad.
4. When the violinist exits, applaud for a fine performance! :-)
Adaptions:
You can give your child instruments to play; like a drum, shakers, etc. and they can describe the pictures on their own through instruments if they're not quite into vocalizing a description.
Or, if you are savvy on an instrument, you can go through the book with them as you have your own piano/guitar/violin/flute, etc. there to improvise a little on what the pictures make you think of. They will LOVE this. :-)
My boys liked the whole idea, but as I said, are not (yet?) so crazy about Carle's books. So, we tried this later with one of their favorite Robert Munsch books (Boo!) and they were much more excited and heartily made up songs about those pictures. What can I say? They're my silly boys.
There is also an official animated version on YouTube (Go here!) which is great, but I would save that for after your little one/s have done their own creating. :-)
So, go get this book from your local library or on Amazon/etc. and give it a try!
Have fun!