Over the years a handful of musicians who have worked the jamband club and festival circuits have appeared on American Idol. The most famous might be American Idol champ Taylor Hicks, who is also the subject of recent Jambands.com feature. The current season of American Idol features yet another musician with ties to the core jamband world—Caleb Hawley. The singer/songwriter’s resume includes opening spots for people like Dave Matthews Band, Rusted Root and Edwin McCain, as well as appearances like Telluride and the Falcon Ridge Folk Festival. Hawley is also a former student at the Berklee College of Music. He will appear at Ardmore, PA’s Milkboy Coffee tomorrow.