The Big House (2004)

S1E5 The Anniversary Party

Kevin wants to express his affection for Aunt Tina and Uncle Clarence, so he persuades his cousins to organize an anniversary celebration for their parents. However, things take a disastrous turn when Kevin accidentally uncovers a shocking family secret: Tina and Clarence tied the knot two years after Warren's birth, a detail they've conveniently kept from their kids.