Believe it or not, I have actually enjoyed Tom Arnold's uniquely ping-pong-like career. He goes from "True Lies" to Fox Sports' talky sports TV show to late night guest appearances and manages to be entertaining at every turn in spite of his lack of talent (OK, marginal talent).
But that's in supporting roles, or just being his bizarre self. He is not made to carry a movie, and in "The Stupids" he is asked to do just that. It's like taking a humorous "Budweiser: True" commercial and stretching that moment of humor into a 90-or-so-minute film. Just doesn't work.
The Stupids are a family, and they're not just stupid, they are CHEERFULLY stupid. Delighted to be stupid. Deservedly stupid. Willfully, gloriously, hopelessly stupid. Clueless? These people can't even spell the word, and they'd be sure it means someone who doesn't own the "Clue" board game.
The movie is even more stupid. I guess that's why there is such a wide divergence of opinion here. If you enjoyed "Dumb & Dumber," you might like "The Stupids." If not (and obviously I hated it), then you won't want to waste your time with a family of grinning morons who dress and act like old-time vaudevillians and '50s TV families but don't seem to know the difference between up and down. Judgement call; the ball is in your court.