(Episode 5 is a Treehouse of Horror episode, not watching that)
When Bart is caught for playing pranks on the teachers, Principal Skinner reveals to Bart that he is not the greatest prankster ever at the school. Bart sets out to discover the identity of this prankster. After looking through archives of the school paper, he discovers that there was two week gap in its publication, and that there was a change in Skinner's appearance before and after the gap.
Groundskeeper Willie tells Bart that he was once the school swim instructor, and that Principal Skinner was a laid-back principal until "Night of the Wigglers." A prankster locked Skinner in a pool full of earthworms for an entire weekend. This experience changed Skinner's personality for the worst. Willie tells Bart that the prankster was named Andy Hamilton.
Bart meets Andy Hamilton and finds out he is unemployed and lives with his mother. When Lisa calls Andy a "loser", Bart gets him a job as Krusty's assistant, but is angry when Andy quits after one day. Bart gets him rehired and goes to checks on him. But when a truck full of earthworms drives into the studio, Bart is terrified that Andy is repeating the "Night of the Wigglers" prank (in the process of trying to stop Krusty.
He discovers that it is part of the show and that Andy has been hired as a writer for Krusty's show. Andy says that his pranking days are over, and thanks Bart for believing that he could grow up.
Elsewhere, Marge is criticized by other Springfield mothers for serving unhealthy snacks at their "Midday Mommies" meeting. She burns the family's junkfood. The family purchases organic food at a local market, but Marge gets criticized again when she uses non-stick bakeware and plastic (7) drinking bottles. The other mothers storm away.
My thoughts:
Blackboard Gag: Dr. Otto's "Wellness Clinic". I would never go there. (B)
Chalkboard Gag: Halloween does not kick Thanksgiving's ass. Eh, it's OK. (C+)
Couch Gag: The Simpson's sing the Twelve Days of Christmas with different Springfield citizens. Funny to watch but it's too long. (B+)
Storyline: This was a strong episode plot-wise. Bart's characterization was great. Him actually looking at Andy played out nicely as well. At first he's in awe and absolutely loving it, but then Lisa points something out to him and that causes him to reanalyze his original opinion on Andy. Seeing Bart lecture Andy on actually growing up was something great to see. Bart really did sell the episode, though. The Milhouse abuse was a bit over-the-top, but Andy was a pretty good character and him with Bart worked.
The Marge story was okay? It had some amusing kids song parodies, and a funny joke about the grocery clerk reading off their order. I did not like the hiding junk food scene. C'mon, that was pointless and stupid.
There weren't many jokes after the first act though. I liked the flashbacks with Willie, Skinner, the newspaper headlines, they were good. Moleman falling out of the ambulance,
Abe showering, and Skinner watching Krusty were decent mini-jokes after the first act.
One last thing: Lisa's LOSER scenes was absolute CRAP. It was overdone and I'm not a fan of it.
Overall, not a bad episode, but there were some flaws.
At the water park with the family, Abe meets a journalist named Marshall Goldman. Goldman is interested of hearing Abe old stories, and Abe is happy that someone cares about his stories. Marshall publishes Abe's story in the Springfield Shopper, and Homer is shocked that other people find Abe's stories interesting. 
In his next story, Abe tells of giving a not-yet-famous Clark Gable a shoe shine at the Springfield railway station and lending him a copy of Gone with the Wind, but still remembers his anger at not being paid. Marshall writes up this story as well and Abe's fame grows. Homer decides to visit his father, but Abe tells him off, suggesting that Homer only wants to spend time with him now that he is famous. Marge tells Homer that is angry with himself for not having spent more time with his dad. 
Homer listens to Mr. Burns' story and writes his own column. He takes it to the Springfield Shopper (where it is quickly shredded). While at the newspaper office, Homer sneaks into Marshall's office and discovers a manuscript that Marshall intends to submit for a Pulitzer Prize. The manuscript states that Abe is dead and Homer realizes that Marshall intends to kill Abe. 
The B-plot was fine, it had a pretty decent start, and Lisa taking it along, but that’s where it lost its base, after she lost it. It was a great turn to see Bart actually holding more morality than Lisa this time. But Bart gets his sewer adventure and that was it… It just ended with the lamb being ripped in two after saving him. Oh well, I wished the B-plot had a resolution. Also, Nelson was annoying in this episode.
When the power goes out during a blizzard, Bart participates in a pretend fashion show put on by Lisa and Maggie. When he notices the bond shared by the two girls, Lisa suggests that he's jealous because he does not have a brother. That night, Bart dreams about being in a park with lots of brothers, such as the Wright Brothers, the Mario Brothers, the Mannings (Cooper, Eli and Peyton), and more. Bart awakens with the realization that he wants a brother.
Lisa becomes interested after she happens to mention in the witches' Circle that she wishes she did not have to hand in her unfinished art project, and her wish comes true when Miss Hoover gets a stomach virus. The girls ask Lisa to join their group and she accepts. But before she gets inducted, Chief Wiggum arrests the three girls on suspicion of witchcraft. 
When Bart is caught for playing pranks on the teachers, Principal Skinner reveals to Bart that he is not the greatest prankster ever at the school. Bart sets out to discover the identity of this prankster. After looking through archives of the school paper, he discovers that there was two week gap in its publication, and that there was a change in Skinner's appearance before and after the gap. 
Meanwhile, to raise money, Marge and her "Charity Chicks" group decide to follow the Springfield Police Department's "sexy" calendar. At the photo studio, Marge does not want to show any skin. But Julio, the photographer, loosens her up with red wine, and she ends up revealing more than she planned. Marge and her erotic poses are soon on calendars which has everyone in Springfield talking about. 
Back at the plant, Carl makes Homer his new assistant. But when Marge wants to make love with Homer, he is too exhausted to satisfy her. Homer tries to make up for it by taking Marge out to a hotel. They try to have a romantic night together, Homer receives a phone call from Carl who tells him they are going to Paris on a business trip. When Homer leaves for Paris the next morning, Marge invites Ned Flanders and his children for dinner.
In Paris, Carl flirts with a beautiful woman, and he tells Homer that he plans to extend their stay indefinitely. Homer gets upset, and walks through the streets where everything reminds him of Marge (and Moe).
Storyline: I thought it was good. I don't think Homer and Marge's characterizations were so odd. I do think Flanders was maybe a little bit out of character, they got a little too fast to the kissing scene, though maybe the wine helped a little. The episode was a little disjointed with the calendar thing having a very thin relation with the main plot, but whatever, I'll let it go. I liked Carl getting promoted. It was a very good idea since he's always been smarter than Homer and Lenny. They did a good job making him a little bad, but without overdoing it. The backgrounds in Paris were nicely done, especially during those small music montages.