Theatergoers who venture to Stratford, Ontario, for Shakespeare might want to check out this season's other plays and musicals. "The Tempest" and "The Comedy of Errors" bear witness to Stratford's commitment to the Bard, while other plays, written and set in the 20th century, also are worthy. "The Tempest," Shakespeare's last solo-written play, is enhanced by magical stage effects alluded to in the text, and "Comedy of Errors," Shakespeare's first comedy, is as knockabout funny as it should be.