Castle suggests to Beckett that the two of them should have a signature line. He then pitches two: "She's armed, he's dangerous." and "A new chapter in crime solving." Both are promotional tag lines used for the show.
The whole talk-show setup is almost identical to Conan (2010) hosted by Conan O'Brien (e.g. Hank McPhee/Andy Richter). Even the cup that sits on Bobby Mann's desk is exactly the same as O'Brien's "Eisenhower-cup".
When talking about the character of Mickey Reed and his possible connection to the murder, Castle says 'Oh Mickey, not so fine.' He is para-quoting part of the lyrics to 'Mickey' by Toni Basil ('Oh Mickey, you're so fine.'). The video for that song was one of the most popular music videos in the early days of MTV.
Both actresses who played Bobby Mann's wives were on two separate hit sitcoms in the 90's. Nicholle Tom (Cindy Mann) played Maggie on The Nanny (1993). Beth Broderick (Barbara Mann) played aunt Zelda on Sabrina the Teenage Witch (1996), a show in which a young Jon Huertas made several guest appearances.
Guest star Tom Bergeron is the host of Dancing with the Stars (2005), Castle (2009)'s lead-in program.