As an actor, Mark Rubald communicates a radiant decency. When he's on stage, you just plain like him; you want him to be happy and succeed. So he was perfectly cast as a good-natured working stiff in Curious Theatre Company's production of Circle Mirror Transformation. You could see how puzzled Schultz was by all the arty stuff going on in these acting workshops, how intrigued by sexy little vixen Theresa and how sad when their affair fell apart. And yet you knew he'd carry on, as calm, kindly and competent as before.