When fat Barney and ugly Robin are fighting, the music playing in the background is "Murder Train" by The Foreskins, the song Robin's ex-boyfriend played with his band in the "Sandcastles in the Sand." This song is used often throughout the series after its original appearance for different fighting montages.
Barney exclaims "Catchphrase" while describing his and Robin's relationship. Neil Patrick Harris was the spokesperson for the game Catchphrase in the early 2010s