Four Great Women and a Manicure - S20-E20
Trivia: During the couch gag, the Simpsons run through different places (as spoofs of different TV shows). One of the places they run through is the bar from Cheers. When they all sit down, Sideshow Bob walks through the door. Kelsey Grammer does the voice of Sideshow Bob, and starred as Doctor Frasier Crane in Cheers.