When Kramer takes the number from Jerry he tears it 3 times. When he throws it up in the air in another scene there're many more pieces than before.
George says to Jerry that the penis "wins until your forty" but Jerry Seinfeld was nearly 40 at the time of the episode.
While Elaine is looking through the closet, Kramer strikes another match and begins to light his already lit pipe. When the landlord starts talking to him, the match is gone and he puts his hand in his pocket!
George: You won't think I'm a bad person?
Jerry: Too late for that.
Kramer: I'm your fiancé. Peter Von Nostrand.
George: Where'd you meet her?
Jerry: I met her on an elevator.
George: On an elevator? You met a woman on an elevator?
Jerry: Impossible, right?
George: You got less than 60 seconds. It's like dismantling a time bomb.
Landlord: (on Babs) The woman used to walk around here half naked, sucking Colt .45 from a can. Her big fat stomach hanging out, orthopedic hose up to her knees, screaming down the hall, 'Come back to bed, Albert, you big hairy ape, and bring back that box of Danish!'
Kramer: You got butchered.
Jerry: Isabel? She is the most despicable woman I have ever met in my life. I have never been so repulsed by someone mentally and so attracted to them physically at the same time.
George: Very exciting, very exciting, it's like watching a birth!
George: I'm going straight to hell, no two ways about it.
George: It's like going to the bathroom in front of a whole bunch of people and not caring.
Jerry: It's not like that at all!
Jerry: It's like my brain is facing my penis in a chess game. And I'm letting him win.
George: You're not letting him win. He wins till you're forty.
Jerry: Then what?
George: He still wins but it's not a blowout.
Kramer: You're as pretty as those girls, you just need a nose job!
This episode features one of the first scenes which Julia Louis-Dreyfus had the hardest time getting through without laughing. She continually burst into giggles at the sight of Michael Richards as Kramer stuffing his pipe with tobacco, and he was displeased with her inability to get a grip, insisting that she was throwing off his concentration. Her giggly fits would interrupt filming of many later scenes throughout the show's run, much to Michael's annoyance.
In the scenes where Jerry's brain and penis play a metaphorical game of chess, the penis is represented by Seinfeld wearing a combat helmet (of the style worn by the US military from the 1940s to the '80s).
This is the first episode where Kramer uses Dr. Von Nostrand. He uses it to pretend his is the fiancé of Elaine, Elaine is pretending to be a guy's daughter to get Kramer's jacket back. Kramer uses this alias in a few other episodes including; "The Package" and "The Slicer."
In this episode George mentions he is from Long Island, whereas in other episodes he states that he grew up in Queens. Technically Queens (and Brooklyn) are located on the western end of Long Island. According to some New Yorkers saying that you are from Queens and saying that you are from Long Island are entirely different things. It must be one of those social things, like being "from the other side of the tracks."
While his brain is playing his penis in a chess game Jerry says, "One for all the marbles." Kramer uses the exact same line later in "The Betrayal."
Jerry: My nose, my nose, my kingdom for nose.
This is an allusion to Shakespeare's play "Richard III" in which the eponymous character speaks the immortal line: "A horse, a horse, my kingdom for a horse."