HBO announced Saturday at the Television Critics Association that it has renewed "Real Time with Bill Maher" for two more seasons, through 2018. The premium cable network says that the series -- which recently covered both the Republican and Democratic National Conventions -- averaged 4.4 million viewers this past season, the show's most-watched since 2003. Programming President Casey Bloys said, " Bill Maher's fearless and irreverent insights make him an important voice of common sense."