After getting busted on a DWI ("driving while intoxicated," not DOA ["dead on arrival"], as Chief Wiggum learned) charge[[note]]even though he passed the road test before Barney told the cops to give him a Breathylizer test, and Barney was never arrested either, since he drank almost as much as Homer did[[/note]] after sneaking out of work to go to a Duff Beer Factory tour, Marge urges Homer to go 30 days without beer. Meanwhile, Bart destroys Lisa's steroid-injected tomato and becomes an unwitting test subject in her new science fair project: "Is My Brother Dumber Than a Hamster?"

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!!Tropes featured:

* BedtimeBrainwashing: The episode opens with Principal Skinner awarding Bart first prize at the school science fair. The phrase "first prize" echoes until the scene transitions to reveal that Lisa was saying this into Bart's ear while he was dreaming because she was "just screwing with [his] mind."
* YoungerThanHeLooks: Hans Moleman is revealed to be 31 years old and looks old because of severe alcoholism. Before anyone cries "NegativeContinuity!", this does tie in with the birth date on his driver's license, as seen in "Selma's Choice," which is August 2, 1961 (which would make him around 31 to 32 years old at the time of this episode's premiere).