The (current) title for episode 4.23 of The Mentalist is "Red Rover, Red Rover", written by Tom Szentgyorgyi. The episode will be linked with the season finale, but will air in a different night. The Season Finale, episode 4.24, will be called "The Crimson Hat" and, of course, is written by series creator Bruno Heller.
Don't forget to follow the awesome Ashley Gable (my favorite writer) on twitter: @Ashley_Gable.
Source: The Mentalist Writer.