Christopher Locke created The Analog Tele-Phonographer, a mobile phone sound amplifier made using a broken trumpet:
This device was made from a salvaged trumpet and assorted machine parts. The base is steel, the legs that hold everything up are stainless steel, and the cradle that holds the telephone is also steel. The horn is brass. All of the steel has been treated with a brown patina, and the entire unit has been coated with a gloss clear coat.
(Via Laughing Squid)