John Cage - Sonatas and Interludes for prepared piano
Cage (1912-1992) was an American composer, one of the most important in the avant-garde movement. He is doomed to be remembered mainly for the notorious 4′33″, which is performed in the absence of deliberate sound. Many of his other compositions show an original great mind at work as well. A personal favourite of mine is his Sonatas and Interludes for prepared piano from 1948 (a piano with its sound altered by objects placed between or on its strings or hammers). Relevant links below (YouTube in five parts: 1, 2, 3, 4, 5).