Ashfield’s Double Edge Theatre celebrates its 25th year this weekend with tales of Merlin, Arthur and the Knights of the Round Table. The Magician of Avalon is a collaboration with Charlestown Working Theatre of Boston, q-Staff Theatre of Albuquerque, New Mexico, European performers and local players, and is a sprawling work taking place indoors and out at the Double Edge farm in Ashfield. Fire-breathing, puppetry, Celtic singing and feats of dramatic eloquence of all kinds offer a blazing spectacle in the hills. For more info, visit www.doubleedgetheatre.org.