1. Exit 9B
Mordecai and Rigby must save the park after the rest of the gang are brainwashed.
Regular Show — Season 4
2. Starter Pack
Mordecai and Rigby want to stop Muscle Man from screwing with Thomas.
3. Terror Tales of the Park II
While on their drive to a Halloween party, Mordecai and Rigby tells scary stories to Benson, Pops, Skips, Muscle Man, High Five Ghost and Thomas.
4. Pie Contest
Mordecai and Rigby want to prove to Benson that they can be judges at the pie contest.
5. 150 Piece Kit
Benson wants to prove that he performed a famous drum solo.
6. Bald Spot
Muscle Man wants to hide his bald spot at all costs.
7. Guy's Night
Pops wants to beat the milk challenge to prove he’s one of the guys.
8. One Pull Up
Rigby has never been known for his upper-body strength, so when the park employees have to go into the doctor and get their physicals, Rigby has trouble doing even one pull up, and so he must find a way to do so or get fired.
9. The Christmas Special
The house is decorated, the guests have arrived and it seems like it's the season to save Christmas when the gang finds themselves faced with the task of destroying a present for Santa that has the potential to destroy them and the holiday.
10. T.G.I. Tuesday
It’s Margaret’s last night of freedom before she transfers to a new college. So Mordecai, Rigby and Eileen decide to surprise her with the biggest party of her life. What could possibly go wrong?
11. Firework Run
After Mordecai, Rigby and Muscle Man squander the fireworks that Benson had purchased for an upcoming event at the park, the three have to go and find more to replace them before Benson blows a fuse and they lose their jobs.
12. The Longest Weekend
Muscle Man tries not to contact Starla for an entire weekend.
13. Sandwich of Death
Benson eats a magical, deadly sandwich that Mordecai and Rigby bought, so the trio must travel with the restaurant's manager, Sensei, to find the cure.
14. Ace Balthazar Lives
Mordecai and Rigby want to reunite the band Adrenaline.
15. Do or Diaper
Muscle Man, Rigby and Starla are annoyed about Mordecai's awkward goodbye to Margaret so they try to get Mordecai to tell Margaret how he feels about her.
16. Quips
Skips intervenes to stop his cousin's bad jokes.
17. Caveman
When Mordecai and Rigby meet a caveman, they decide to put his unique prehistoric physique to good use: chugging cheese! But could this caveman actually turn out to be a Neanderthal nuisance?
18. That's My Television
Mordecai and Rigby help their favorite '80s sitcom star, RGB2, escape from the studio lot and into the mountains so he can avoid starring in a revival of his show.
19. A Bunch of Full Grown Geese
Mordecai and Rigby have to get rid of some geese that are causing problems at the park.
20. Fool Me Twice
Mordecai and Rigby want to win the grand prize on a Japanese game show.
21. Limousine Lunchtime
Rigby stains Mr. Maellard's expensive white limousine with a meatball sub, so the guys have to clean it before Mr. Maellard gets back from vacation.
22. Picking Up Margaret
Mordecai offers Margaret a ride to the airport.
23. K.I.L.I.T. Radio
Muscle Man wants a local radio station to play the song he wrote for Starla.
24. Carter and Briggs
The guys enter a donut contest in hopes of winning a cameo on their favorite cop show.
25. Skips' Stress
Skips has to lower his stress for health reasons.
26. Cool Cubed
Thomas must save his brain after he chugs a slushy that freezes his brain.
27. Trailer Trashed
Muscle Man tries to save his trailer after it fails a health inspection.
28. Meteor Moves
Mordecai plans to kiss Margaret at a meteor shower.
29. Family BBQ
Mordecai tries to shake hands with Margaret's father.
30. The Last LaserDisc Player
The guys need to obtain a LaserDisc player in order to watch the director's cut of a cult classic.
31. Country Club
Mordecai and Rigby have to rescue the golf cart from a bunch of rich people at a country club.
32. Blind Trust
Benson must trust Mordecai and Rigby to help get him down a mountain.
33. World's Best Boss
The park employees want to give Benson a special mug.
34. Last Meal
Muscle Man wants to binge on his favorite foods before going on a diet.
35. Sleep Fighter
The park guys must help Muscle Man to stop fighting in his sleep.
36. Party Re-Pete
Mordecai and Rigby must save Benson from an evil party company.
37. Steak Me Amadeus
Mordecai wants to ask Margaret to be his girlfriend.