"A Narm is a moment that is supposed to be serious, but due to either over-sappiness, poor execution, excessive Melodrama, or the sheer absurdity of the situation, the drama is lost to the point of becoming unintentionally funny. It can be extremely subjective.
It is named for the famous scene in the last season of Six Feet Under, where the main character Nate suffers a brain embolism. He suddenly grabs his right arm and repeats "Numb arm!", but it quickly becomes "N'arm! N'arm!" Despite being the climax of one of the best shows HBO has ever created, the scene was overwhelmingly found by fans and reviewers to be funny rather than sad."
http://tvtropes.org/pmwiki/pmwiki.php/Main/Narm