One of New England’s longest-running open mics, Stone Soup has been gathering poets since the 1970s and still carries that communal, anyone-can-read spirit. On second and fourth Wednesdays it meets in person in the brick-and-timber lofts of Fort Point’s arts district, often with a featured reader before the open list. It’s a welcoming, unpretentious room where new voices and old hands share the same battered mic.