Following seven great seasons of "The Mary Tyler Moore Show," Mary made an ill-fated attempt at success with this musical variety and sketch comedy show, which was shelved after producing just a handful of episodes.  In the cast were familiar TV and film character actors Dick Shawn and James Hampton; up-and-coming stage actress Swoosie Kurtz; Judith Kahan ("Mary Hartman, Mary Hartman," and "Forever Fernwood"); and two relatively unknowns: Michael Keaton, and a gap-toothed, 31-year-old named David Letterman.