Tonight, Community returns for its fifth season, with Dan Harmon back on board as showrunner after he was fired in 2012. Prepare with a look back at the show's many self-referential and pop culture jokes, Easter eggs, and callbacks.

1. Beetlejuice, Beetlejuice, Beetlejuice

This was a sight gag three years in the making. Once a season, a character from Community would mention the character Beetlejuice from the Tim Burton film. In the third season, when Annie mentions the name, you can see Beetlejuice in the background passing through the frame.

2. Abed Delivers a Baby

In season two, Abed is rarely featured in the episode “The Psychology of Letting Go”: We see him only in the background in a story arc that involves a couple. First, Abed first meets a pregnant woman; then, the father of the unborn child confronts Abed thinking that his girlfriend is having an affair. Later, Abed is seen in a pickup truck helping to deliver a baby.

The couple having the baby was first seen during season one in “The Politics of Human Sexuality,” where you can see a couple in the background throwing away a condom before having sex. More than nine months later, in season two, Abed helps deliver their baby.

Later in season two, Shirley goes into labor and the study group has no idea what to do—except for Abed, who says he has experience delivering babies.

3. Abed’s Visit to Cougar Town

Abed’s favorite TV show is Cougar Town: In the episode “Critical Film Studies,” he mentions to Jeff that he was invited to visit the set of the TV comedy. In the Cougar Town episode “Something Good Coming - Part 1,” you can see Abed in the background.

Later in season two, Cougar Town's Busy Phillips and Dan Byrd make a cameo appearance in Community.

4. Apartment 303

In the episode “Remedial Chaos Theory,” Troy and Abed are having a dinner party at their new apartment. Britta and Annie show up first and comment on whether the party is in apartment number 304 or 303.

TV episodes are numbered with the number of the season first and then followed by the episode number itself, so season 3, episode 3 is 303. While the episode was aired as the third season’s fourth episode, it was originally supposed to air as its third, thus the 303 and 304 confusion.

5. Gwynnifer

Series creator Dan Harmon is very active on Twitter and will actually reply to users if they have a question or comment. But when Twitter user @Gwynnifer called him a fat bigot, Harmon used her name as a punching bag on the TV show. The name Gwynnifer is also used as a secret code between Britta and Jeff’s secret relationship. Their love affair was later revealed in the episode “Paradigms of Human Memory.”

6. Rowboat Cop

In the episode “Aerodynamics of Gender,” Shirley, Annie, and Britta use Abed’s eerie attention to detail to be ruthlessly honest with the girls of Greendale. Abed compares his gift to Robocop, which Britta mistakes for Rowboat Cop.

In Abed’s heads up robot display, he has a list of events that foreshadow future episodes like “build a blanket fort,” “call mom for Christmas,” and a reminder for Troy’s birthday.

7. Latvian Independence Parade

In the episode “Conspiracy Theories and Interior Design,” Troy and Abed make a giant blanket fort throughout most of Greendale Community College. A small Latvian Independence Parade marches through the massive blanket fort. The episode originally aired on November 18, 2010, which is the same date as Latvian Independence Day.

8. Annie’s Boobs Steals The Pen

At the very beginning of the episode, unbeknownst to the characters, we very briefly see that Troy’s pet monkey Annie’s Boobs stole Annie’s pen. The whole episode is spent trying to figure out who was the culprit.

9. Mad Men

The study group finds out that a student at Greendale has a crush on Abed. To see if he has the ability to flirt with women, Abed and Annie role-play a casual encounter as Abed channels Don Draper from Mad Men to seduce Annie. Actor Alison Brie plays both Annie Edison on Community and Trudy Campbell on Mad Men.

10. Daybreak

Multiple characters through season three of Community hum musician Michael Haggins’ smooth jazz tune “Daybreak.” It starts with Abed in season three’s Halloween episode “Horror Fiction in Seven Spooky Steps,” then continues with Troy in “Foosball and Nocturnal Vigilantism,” and then later with Annie in “Contemporary Impressionists.”

11. Shirley’s Friend Gary

Gary was Shirley’s unseen Finnish friend at Greendale before she met the study group. During the show's first season, she tries to introduce him to the study group, but they are not keen on the idea of Gary joining. Britta calls him a boring buzz kill, while Shirley continues to defend her friend. Later in season one, Gary transfers to another school.

12. Derrick Comedy

In season two, Abed arranges a wedding ceremony for Jeff and Britta. The people Abed hired for the wedding ceremony are some of the members of the sketch comedy group Derrick Comedy; Donald Glover was a former member.

13. Britta’s Dinosaur

Much like the other members of the study group, Britta has psychological trauma that she’s repressed from her memory. Britta’s trauma comes in the form of dinosaurs. It's first discussed in the season one finale by Professor Duncan, then re-occurred as a sight gag in season two’s Halloween episode where Britta dressed as a T-Rex, and later in season three, when evil Abed psychoanalyzed Britta’s state of mind.

14. Theo Huxtable

Malcolm-Jamal Warner played Shirley’s estranged husband Andre on Community. In his first appearance, Jeff compliments Andre’s sweater as Andre mentions that his father gave it to him. The sweater is a reference to Bill Cosby, Malcolm-Jamal Warner’s TV dad on The Cosby Show.

15. Colonel Sanders

When the study group is trapped in the Kentucky Fried Chicken spaceflight simulator in season two, Pierce has a panic attack and hallucinates that Colonel Sanders is trying to kill him. Pierce screams out “Get off my mommy, I’m her man” when he destroys the simulator display.

Later in season three, we’re introduced to Pierce’s father Cornelius Hawthorne, who looks exactly like Colonel Sanders.

16. 1980s Martin Scorsese

In the episode “Physical Education,” Jeff takes a billiards class where he gets into a heated confrontation with his instructor. During the episode’s climax, there’s a cutaway to a man who looks like a young Martin Scorsese from the 1980s. The episode is a parody of the movie The Color of Money directed by Martin Scorsese.

17. Fletch Lives!

On the official Greendale Community College website, Pierce Hawthorne is listed in the Student Spotlight section. In his bio, the movie Fletch is listed as one of his favorite movies. Of course, the actor who plays Pierce is Chevy Chase, who played the character Irwin M. “Fletch” Fletcher.

18. All Tomato

In the episode “Studies in Modern Movement,” Annie moves into Troy and Abed’s new apartment. As the only adult, when she gets annoyed with their childish behavior she threatens them with an ultimatum. A few episodes later, in “Pillows and Blankets,” Troy and Abed fight over territory for their respective forts, so Troy threatens Abed with an “all tomato” to take down Pillow Town. Troy doesn’t know how to pronounce the word “ultimatum.”

19. Danielle Harmon

In the first season's finale, Greendale’s annual Transfer Dance is renamed to the Tranny Dance. Dean Pelton reads off the runners up for the Tranny Queen contest. One of the names he reads is the feminine version of Dan Harmon’s name, Danielle.

20. Donald Glover as Spider-Man

In the episode “Anthropology 101,” the opening shot features the members of the study group waking up for the first day of school. Troy is visibly wearing Spider-Man pajamas. During the summer of 2010, Donald Glover campaigned to audition for the role of Peter Parker in The Amazing Spider-Man reboot film.