Maine button accordion player Dan Possumato and friends - Belfast’s Jim Hyland on guitar, fiddle and vocals; and special guest Jody Johnstone on whistle – kickoff the weekend before St. Patrick’s Day at Camden Opera House, 29 Elm St. General admission tickets are $15 in advance at camdenoperahouse.com, $20 day-of-show (cash at the door, please). Doors open 7 p.m. Sponsored by the Community Arts Fund and 40 Paper.