Harold and Kumar's second stoner adventure gets them incarcerated at Gitmo 
  after they carry a bong on a plane and people mistake it for a bomb. They 
  break free immediately, so the film is not really about Gitmo at all. The real 
  plot is about their trek to Texas to disrupt the wedding of Kumar's 
  ex-girlfriend. During their peregrinations they encounter various comic adventures while 
  Homeland Security follows their trail. 
  This episodic flick has quite a high rating at IMDb, which is surprising for a 
  stoner film, but I was lukewarm toward it, despite the fact 
  that I like stoner humor and enjoyed the film's predecessor.
  Why? Well, if you think about the great lowbrow comedies like There's Something About 
  Mary and Bill and Ted's Excellent Adventure, you will realize that they have 
  certain things in common:
          
            - an involving story which could stand on its own without the surrounding 
    farce
- memorable comic characters
- some laugh-out-loud moments
- originality in the raunchy bits
- heart
- a touch of art and imagination
This film comes up short on too many of those requirements.  There are 
  no big guffaws, the story is completely uninvolving, and the sentimental 
  moments are totally forced. In fact, it wouldn't even be fun to watch stoned, 
  because Harold spends more than half of the movie being a wet blanket, 
  grousing about Kumar's irresponsibility and inability to apologize. What the 
  hell kind of stoner is this guy? Dude, chill out. Your buddy is a stoner. Of course 
  he's irresponsible. It's you, the uptight stoner, who doesn't seem to fit in 
  the picture! Harold is the kind of guy who wants to get baked so he can dust the 
  furniture and study the tax tables. To be honest, this film's version of Kumar 
  is also too uptight to be a lovable stoner, albeit in a different way. He's 
  always turning every situation into a confrontation of some kind instead of 
  just takin' 'er easy. This Dude does not abide.
  The greatest weakness of the film is that it simply lacks originality and 
  imagination. It's 
  not unpleasant to watch, but I felt I had seen it all before. Most 
  of the humor consists of the same old tired jokes about the same old subjects: 
  unpleasant bodily functions, petty government bureaucrats, prison rape, inbred 
  rednecks, tough-looking guys who turn out to be sensitive, and so forth. The 
  best ideas were lifted from the first H&K movie.
  I did enjoy the sound track, especially a raunchy song called "My Dick, and the film 
  does have one memorable comic character: 
  Neil Patrick Harris, who plays himself in this sequel, as he did in the 
  original, and is even crazier this time around. Harris-as-Harris, wacked-out 
  druggie and pervert with a monumental ego, is absolutely brilliant every 
  minute he is on screen. The people who created this film should have made 
  Harris the star, because his fictional alter ego is the Hamlet of druggies, madness and all, while 
  Harold and Kumar are merely the Rosenkrantz and Guildenstern. Unfortunately, 
  Hamlet is relegated to a walk-on.