Not only the worst Simpsons episode to date, but the worst episode of ANY show in the last ten years! The show was so unfunny it actually sucked humor out of the room. If there had been a comedian present, he probably would have imploded. On top of the below-zero humor content, the story was very predictable and trite. I've seen better stories in tampon commercials.
That's my rant. Your mileage, of course, may vary.