MODERN FAMILY - "Game Changer" - It could not be more perfect that Phil's birthday and the release date of a hot new product coincide, and he wants nothing so much as to be one of the first people to get one; this is Claire's mission. Meanwhile, before coming to Phil's party, Mitchell is preoccupied with a new found desire to toughen up, Cameron gets himself involved in a neighbor's marital problems, and it's Jay against Gloria and Manny in chess, on "Modern Family," WEDNESDAY, MARCH 31 (9:00-9:30 p.m., ET), on the ABC Television Network. (ABC/ERIC MCCANDLESS) TY BURRELL, SOFIA VERGARA, ED O'NEILL, RICO RODRIGUEZ