Mark Morris masterpiece 'L'Allegro' airs on PBS tonight

One of the happiest, most uplifting and imaginative dance productions will air on PBS's "Great Performances" at 9 p.m. tonight: Mark Morris' "L"Allegro, il Penseroso ed il Moderato." This full-length modern dance accompanied by Handel's oratorio of the same name is perfect fare for early spring. Seeing it could very well make you feel better about the human condition.