Fred Armisen and Carrie Brownstein play an ultra-cool pair of hip parents with two sons, the elder of which (Bart's age) is named Tyrannosaur, and voiced by Patton Oswalt. Now I grant you, hipster bashing is not exactly a cutting-edge trend. (In fact, later that same night I caught a rerun of a hipster-bashing episode of King of the Hill which first aired in 2008.) But that doesn't make it any less funny when it's done right.
"The Day The Earth Stood Cool"
"Here, have a bracelet made of a '70s educational film strip."
This episode had the perfect combination of rapid-fire one liners ("Portland… I've heard of people being from there") plus a madcap energy that carried the plot along too fast for second-guessing some of its odder turns. (There's no time to question Marge's decision not to breast feed Maggie! Hurry - The Decemberists are about to play a hipster mostly-acoustic version of the Star Trek: TOS fight scene music!)
Aside from being entertaining, and changing up the show's dynamic in interesting ways, this episode also managed to get right at the heart of why hipsters are so hatable. Most hipster-bashing episodes rely on annoying catch phrases and the impenetrable-to-outsiders hipster culture. But The Simpsons knows that hipsters are hatable because they are mean-spirited to things that fall outside the Hipster Approved List (witness T. Rex's behavior towards Homer's gift), and they exhibit a patronizing sort of domineering behavior (Marge vs the self-righteous breast-feeders, and I can assure you, that incident was not too far from the truth).
In other words, hipsters aren't just "cooler than thou," they're also not very nice people. And putting the Simpson family up against mean people who are also socially successful is a recipe for funny.
The clash between the Simpsons and the hipster army also highlights something that's easy to forget: the Simpsons are a blue-collar family. They can't even afford to buy a Mapple MyPad, and they certainly can't afford the hipster lifestyle.
This episode could easily have failed. What really saves it is the relentlessly specific satire of hipsterdom. It's easy to make lazy jokes about hipsters, but in every single case, the writing team obviously pushed itself just a little farther. From the pitch perfect New York Times headline ("Under The Cooling Towers, A Trendy Oasis Beckons") to Marge's bewilderment upon first encountering The Onion, to Disco Stu strolling past in a Daft Punk helmet. The amazing bevy of little details is what really kicks this episode into the upper echelon for the last few seasons.