HAPPY ENDINGS - "The Shershow Redemption" - A sudden invitation to the wedding of old friend Shershow (T. J. Miller), a notorious slacker, brings unexpected consequences; Brad and Jane discover something shocking about their own marital status; a depressed Penny convinces Derrick (Stephen Guarino) to pose as her fianc; and Shershow's fiance (June Raphael) fears that Alex is the "wedding jinx," on "Happy Endings," WEDNESDAY, MAY 18 (10:00-10:30 p.m., ET) on the ABC Television Network. (ABC/MITCH HADDAD) ADAM PALLY, CASEY WILSON, ZACHARY KNIGHTON, ELISHA CUTHBERT, DAMON WAYANS JR., ELIZA COUPE