We ventured into the Museum of Making Music after the rain prevented us from going to the Wild Animal Park. This proved to be a great rainy day activity. The museum is in an unsuspecting office park. The staff there was very welcoming and eager to answer our questions.
After entering through the gift shop, with someone for every music lover in your life, you begin the exhibit with instruments and information about music style from 1890. As you walk through the musuem, you also travel through time musically, with interactive exhibits and displays of instruments and musical styles as they develop up to the present day. It was fun to play samples of music I didn't know about, as well and dance and sing along to '80s tunes.
There were some really impressive instruments, including the Leo, which is like a huge synthesizer/hammond organ. See the picture.
The last exhibit room has instruments, such as an electric bass, a theramin, turn tables, electric guitar, an organ, and a midi computer synthesizer to play yourself. Most of the instruments had someone playing them, so I didn't try any myself.
They also have a great website with photos and examples: http://www.museumofmakingmusic.org