Castle and Beckett investigate the murder of the creator of a popular sketch comedy show.
- All Part of the Show: When Beckett goes to arrest Gene, he runs onto the stage where they're performing the final skit of the night, which happens to be a spoof of Castle and Beckett's cases. When the fake Beckett's heel gets stuck in the door trying to kick it down, the real Beckett smashes down the door to tackle Gene and make the arrest. The audience starts applauding, thinking it part of the show, and Castle and Beckett take a bow.
- The Cameo: Carly Rae Jepsen makes an appearance performing on the anniversary show for Saturday Night Tonight.
- Combat Stilettos: Lampshaded by the SNT head writer when she asks Beckett how she's able to run around on the job wearing heels. Later Played for Laughs in the SNT skit, where part of it involves the fake Beckett (who's wearing a somewhat revealing outfit) getting her heel stuck in a door when she tries to kick it down.
- Do I Really Sound Like That?: Beckett is a bit uncomfortable watching the actress playing her in the skit imitate her gait and mannerisms, asking Castle if she really acts like that. Castle immediately asks what kind of response won't result in him sleeping on the couch.
- Expy: Saturday Night Tonight serves as one for Saturday Night Live.
- Funny Background Event: While Castle and Beckett are asking who gave the drug kingpin a pass to the show, the actress playing the Beckett expy in the SNT skit can be seen comically exaggerating her mannerisms.
- Noodle Incident: In the morning, Beckett learns that Martha has a ritual where she says nothing but her first line for a show she's starring in for two days to prepare. According to Castle, her opening line for the ritual was once "Come on baby, I'll make it worth your while" and it was the most awkward parent teacher conference ever.
- Not So Above It All: At first it seems like Beckett is annoyed at Castle gushing over actor Danny Valentine. Then Teddy starts hitting on her and it turns out she's a fan and starts playing with her hair.
- Oh, Crap!: Mickey acts like a nutbar so he can get out of his contract because he's losing out on lucrative movie roles. He didn't realize he was being questioned for murder.
- O.O.C. Is Serious Business: Beckett is confused when Martha just keeps repeating "Is he dead?" no matter the context. Castle explains that's what she does for the two days before opening night. But this is forty-eight hours before the previews.Castle: Oh, that is weird.
- Performance Anxiety: The morning of the preview show, Beckett notices that Martha was in a bit of a funk, having even stopped with her usual rituals. It turns out that Martha was getting nervous about potential criticism and was thinking of dropping out until Castle encouraged her to go through with it. In the end, Martha's performance ends up getting rave reviews online.
- Shout-Out: Saturday Night Tonight serves as one to Saturday Night Live. The episode title is also a play on the show's opening line.
- Stealing from the Till: Gene had been embezzling money from the company, and with the threat of exposure hanging, so he kidnapped Evelyn and ransomed her for the money he stole. Unfortunately, Sid recognized Jean at the drop and confronted him about the expenses, so he killed him for it.
- Stylistic Suck: The sketches we see from Saturday Night Tonight are ... not funny.
- Take That!: While looking at posters of past cast members for Saturday Night Tonight, Castle notes how they're all comedy geniuses, except for that one season that had puppets.
