One of the greatest car and musical instrument museums is located in Southern California. Unfortunately, nobody has ever heard of it. It is about 20 minutes north of LA but it is definitely worth the trip. And admission is free. Plan on spending a lot of time there.
Here is the link to the Nethercutt Museum.
Welcome to The Nethercutt Collection! - Flash
There are actually two museums, one across the street from the other. Use need to call and make reservations.