NPR's guide to the running gags from the show.
A mysterious individual with his own theme song.
6 episodes feature this joke:
MRF stands for "Mentally Retarded Female."
The theme is heard when Donnie Richter explains the "Openings" grading system.
Mr. F stands for Mr. Franklin — G.O.B. and Franklin's pimp persona.
The Mr. F theme plays behind Argyle Austero as he describes his role in the Fantasticks.
The Mr. F theme plays behind Argyle Austero when he threatens Michael.
The Mr. F theme plays when Michael sees Lucille Austero's demand for $700,000.
Sources: Joke data compiled by Adam Cole / NPR. Episode metadata from The TVDB via a Creative Commons Attribution 3.0 United States (CC BY 3.0 US) license.