The musical duo Castlebay will celebrate what the Celts call Samhain, commonly known as Halloween, on Saturday, Nov. 3, at the New Gloucester Coffee House. Julia Lane and Fred Gosbee’s renditions of traditional and original songs are supported with Celtic harp, 12-string guitar, fiddle and woodwinds. Joining them for the 7:30 p.m. concert will be local musicians Holly Morrison and Sue Mack. Lane and Gosbee have been performing together since 1987. Their new album, “John Earthy’s Tavern,” is a collection of 16 songs celebrating Maine’s history. Admission is $10 for adults, $5 for seniors. The coffeehouse is at the First Congregational-Christian Church in New Gloucester.