Holiday cheer is popping up all over the state this month. In Stockbridge, the Berkshire Theatre Festival mounts its fourth production of A Christmas Carol (December 12-30), adapted by director Eric Hill, who also plays Scrooge. Watertown's New Repertory Theatre revives its crowd-pleasing A Christmas Carol on the main stage, with an appropriately gruff Paul D. Farwell as Scrooge (December 6-17).