Regular Show/Trivia
- Defictionalization: Now you too can be a member of Mordecai and the Ribgys!
- Hey, It's That Voice!:
- Mark Hamill voices regular character Skips, along with the British Taxi from "Ello Guv'nor" among other one-shots.
- Rigby is voiced by William Salyers, who also voiced Reverend Putty.
- Tim Curry as the leader of a group of cannibalistic hot dogs.
- Paul F. Tompkins as the movie store clerk in "Ello Guv'nor".
- David Ogden Stiers as Benson's boss, Mr. Maelard.
- Steve Blum as Utopia and a few other one-shot characters (might be confused with Hamill, listed above).
- Jeff Bennett is a recurring VA for background characters.
- Roger Craig Smith plays Doug the Doppelganger, Low-Five Ghost, and various other voices.
- Starla, Muscle Man's girlfriend, is voiced by Jack.
- Rigby's brother Don is voiced by Paul, of all people.
- April Stewart is Susan.
- Carl Weathers (Apollo Creed) as the King of Basketball in "Slam Dunk".
- ((A Nightmare On Elm Street Robert Englund)) voices "Deer Man" from "Camping Can Be Cool".
- Donald Glover voices Alpha-Dog in "Rap It Up".
- Tyler the Creator Voices Blitz Comet
- James Hong as the Chinese restaurant guy in "Fortune Cookie".
- Robin Atkin Downes voices Gary.
- Troy Baker is Park Avenue in "Under the Hood".
- Linda Cardellini voices C.J. in "Yes Dude Yes".
- Michael Dorn is Thomas, the son of Death.
- The Other Darrin: High Five Ghost was voiced by Jeff Bennett in two episodes, but his other voiced appearances all have Quintel as his voice actor.
- Mordecai's first French actor (Gerald Rinaldi) died in March 2012, so he was replaced by Emmanuel Dekoninck.
- Talking to Himself: J.G. Quintel voices both Mordecai and High-Five Ghost, and Sam Marin voices Benson, Pops and Muscle Man. Both they and Mark Hamill (Skips) voice several background characters as well.
- What Could Have Been
- For "Do Me a Solid", instead of destroying the tape, Rigby originally kept it.
- Margaret was originally not going to wear any clothes like Mordecai, but was changed for obvious reasons.
- In "Mordecai and the Rigbys", there was supposed to be a scene where Mordecai and Rigby ask Benson why there were instruments in the garage. Benson has a flashback when he used to be a hippie where his ex-girlfriend, Veronica, who is also a gumball machine, leaves him for a business man.
- In "Skips Strikes", Skip was originally suppose to have a different secret. Which was him being friends with the Magic Elements.