Tim Ovens plays John Cage · Sonata X for Prepared Piano

I stumbled upon this video through this website http://musicmotionblog.com/ This video features Avant-garde composer John Cage's Sonata X for a "Prepared Piano". Now what is a prepared piano? Shame that a Music Major like me should not know about it. Thanks to Wikipedia, I don't have to go through a chockful of music related textbooks in order to find out about it. It is basically a piano whose sound is changed by affixing or sticking objects like nuts, bolts, rubber plates etc. making it sound more percussive. Sentimental and ear-flaying, here is Sonata X from John Cage's "Sonatas and Interludes" as performed by German pianist Tim Ovens.