THE MIDDLE - "Leap Year" - Because this year is a leap year and Sue's birthday falls on February 29, she is overly excited about celebrating her big day in a big way. But given her parents' track record with celebrations, Sue may need to lower her expectations. Meanwhile, Frankie discovers that tough husband Mike has been taking care of a stray cat at work for years, Brick falls for a pretty girl in his social skills class, and Axl becomes enthralled with vacuuming the house, on "The Middle," WEDNESDAY, FEBRUARY 29 (8:00-8:30 p.m., ET) on the ABC Television Network. (ABC/RICHARD FOREMAN) EDEN SHER, PATRICIA HEATON, CHARLIE MCDERMOTT, ATTICUS SHAFFER, NEIL FLYNN