“Backpack Sunday.” Backpacks collected at Portland churches will be given to patrons at St. Vincent de Paul Soup Kitchen. St. Pius Church, 492 Ocean Ave., Portland. 4-6 p.m. Saturday, 6 a.m.-6 p.m. Sunday. “Snowfall,” the Maine Gay Men’s Chorus winter concert. $15 advance, $20 at door. First Parish Unitarian Universalist Church, 425 Congress St., Portland.