In the end credits of every episode of It's Always Sunny in Philadelphia the credits for the production company RCG (formerly RCH) include a hidden audio message. The messages are recorded by the executive producers (Rob McElhenney, Charlie Day, and Glenn Howerton) and are played backwards.
Season 1 ---
Season 2 ---
Rob and Glenn: - "Is a brown, is a brown, is a brown". - "Good work".
Season 3 ---
All three (singing): "Make it brown" (4 times).
Season 4 ---
All three (singing): "Clown baby, brown clown clown baby, brown clown".
Season 5 ---
Rob: "Next stop - brown town".
Rob: "Sorry for wasting your time and money, but thanks for your money".
Season 6 ---
Glenn: "BROWN - now in HD".
Season 7 ---
Charlie: "Seven seasons of brown".
Season 8 ---
Rob: "The browning's will continue". [PROOF]
Season 9 ---
Charlie (singing): "The eagle's born out of thunder".
- According to Glenn, "RCH never stood for Rob Charlie Howerton". Here is his Tweet from August 13, 2011: "I'll give you guys a hint: RCH is an acronym for a very small unit of measurement. Most carpenters will know the answer". This article says that "a red cunt hair (also RCH, red pussy hair, and red one) is a figure of speech used to represent infinitesimal length".
- Probably, the abbreviation RCG stands for "Rob, Charlie, Glenn".
- At the end of the 1st Season finale, the message had an echo.
- The use of the word "brown" in most of the messages is probably a reference to the band Ween, who used the term to refer to their most outrageous/bizarre/offensive songs. And this show is definitely really, really brown.
- "Clown baby" - it's a nickname, which is was made up by Dennis for Charlie (as the Paddy's underground street fighter). ("Hundred Dollar Baby")