Despite being canceled a year and a half beforehand, Family Guy managed to rise from the dead and began making audiences keel over from laughter once more during their fourth season. It says a lot that the show was revived, and some of the episodes this season would become truly iconic.
Knowing full well that this could be their last chance, the show's writers came out swinging and delivered one of the series funniest seasons, including having the two highest-rated IMDb scores that the show had had up to that point.
The Perfect Castaway, Episode 12 (7.7)
Even die-hard fans of the raunchy comedy can forget that there was a brief stint in season 4 where Peter was a fisherman in order to pay the bills. Tragically, he and the guys get caught in a giant storm during this episode and wind up stranded on a deserted island for months. They manage to get rescued by a cruise ship who brings them home, but it's revealed that Lois married Brian during the time that Peter was away. The family tries to make the new dynamic work, but Lois ends up cheating on Brian with Peter and the two of them realize that they should end their relationship and go back to the way things were.
Untitled Griffin Family History, Episode 27 (7.7)
It only makes sense that if a person's house is being broken into they should hide in a safe room if they have one - what they shouldn't do is then recount their entire family history instead of calling the police. But due to a lack of phone, Peter chose the former and gave his family and the audience a thoroughly detailed history of all of his prior ancestors through the centuries. Some ancestors included a cave-man, Moses, a slave, a silent-movie actor, and the annoying brother of Adolf Hitler.
North by North Quahog, Episode 1 (7.8)
In the very first episode that aired after returning from a year and a half hiatus, the Griffin family got into some serious antics as Lois and Peter decided to go on a second honeymoon to reignite the spark in their relationship. They ended up posing as Mel Gibson to get into his private suite in a hotel, steal his unreleased film "Passion of the Christ 2: Crucify This" and ultimately wind up in a stand-off with the actor on top of Mt. Rushmore. Meanwhile, Brian and Stewie are left to look after Chris and Meg while their parents are away - it goes as well as expected.
Brian Goes Back to College, Episode 15 (7.8)
Brian always prided himself on being studious and well-written and it didn't hurt his ego in the slightest when he began working for The New Yorker. Unfortunately, Brian gets booted from the company when they discover he never finished college, so Brian decides to go back to school and get the last credit that he needs for his degree.
The work proves to be too much for him and he ends up leaving before the final test, only to be inspired by Lois and Stewie to not give up. It turns out not to matter as he fails the test anyway.
Patriot Games, Episode 20 (7.8)
While he wasn't the superstar he was during the earlier seasons, Tom Brady had assuredly established himself among the best quarterbacks in the NFL in 2006 - precisely when this episode aired. Peter runs into Brady at his high-school reunion and he impresses Tom with his quickness and size, resulting in Peter getting invited to join the New England Patriots. Peter takes the offer and immediately begins showing-off and causing on-field incidents that get him kicked off the team and sold to the London Sillinannies, the worst football team in Europe. Peter and his new team eventually challenge the Patriots, but run away upon seeing the gigantic players.
Stu & Stewie's Excellent Adventure, Episode 30 (7.8)
The fourth season had 30 episodes in its entirety and decided to close its comeback season out with a three-episode-special revolving around Stewie finding a man he thinks is his biological father, only to discover that it's actually Stewie himself from 30 years in the future. The final episode of the season closed out the three-episode-arc by bringing Stewie to Stu's time period, Stewie eventually mucking everything up for his future self, and then deciding to go back in time to the moment in Stewie's life where everything began to go wrong and fix it so his future depressing life never happens in the first place.
Petergeist, Episode 26 (7.9)
Peter becomes envious of Joe when he builds a home theater so Peter tries to build an entire multiplex in his backyard. However, upon construction, Peter comes across some ancient Native American burial remains and moves them from their resting place.
This causes the ancient spirits to take revenge on the Griffins by sucking their house into a different dimension. They learn that they can only make amends by returning the ancient remains, but they have to retrieve them from comedian Carrot Top before they can.
The Fat Guy Strangler, Episode 17 (8.0)
Before Robert Downey Jr. became Iron Man, he was voicing Lois' long-lost brother, Patrick, in Family Guy. Lois finds an old photograph from her childhood that reveals a brother she doesn't remember having, but her mother confirms that she does in fact have a brother but he was institutionalized as a child. Despite her mother's objections, Lois goes to meet her brother and checks him out of the mental-clinic, only for things to go horribly sideways when fat-men start turning up strangled all over town and Patrick is identified as the killer. Patrick eventually tries to strangle Peter but Lois convinces him to give up and go back to the hospital.
Petarded, Episode 6 (8.3)
An episode that gained the second-highest IMDb-rating of the season is one that more than likely wouldn't get made today (and for good reason). The Griffins have their neighbors over for game night and Peter begins to think of himself as a genius when he wins a game of Trivial Pursuit. Tired of his arrogance, Brian challenges Peter to test if he's actually a genius - and the results of the test end up saying that Peter is actually mentally developmentally disabled. Peter spends the rest of the episode trying to adapt to life as a "mentally retarded" man (this being Family Guy, the episode uses that term) and uses his diagnosis to justify any horrible act that he can come up with.
PTV, Episode 14 (8.6)
Part of the reason that Family Guy had been canceled in the first place was that it was critiqued for being too obscene for cable television - so anybody with a brain could've guessed they'd make an episode taking a shot at the very people who accused them of being too graphic. The FCC decides to amp up their censors on cable, prompting Peter to start his own television network. The FCC shows up and shuts him down, but eventually ends up "censoring real life" in order to prevent any type of obscenity at all. After a few weeks of everybody being censored, the Griffins drive to Washington D.C. and convince Congress to lift the FCC's censorship ban by pointing out how all of the monuments in the nation's capital look like genitalia.