Denver Cohen is one of the younger radio builders off to a great start. This is his third crystal radio. He's using one of those old time brown germanium diodes. The same type I used when I built my crystal radios when I was a kid. Denver promises that he will be building more radios.
Update June 2010 Denver now has his ham radio General Class ticket. He still is building radios was well as working dx on 20 meters.