One of the time machines that Cassandra partially uncovers in the Library's time travel room is a 1960's era London Police box, an obvious reference to the TARDIS from Doctor Who (2005).
One of the time machines in the Library's collection is a silver car with a California license plate reading "JUSTINTIME". This is an homage to the iconic DeLorean in the Back to the Future (1985) series, although the plate on Doc Brown's car reads "OUTATIME".
The quotes used to expel Prospero come from the following Shakespearian plays, and each hold special relevance to the character who speaks them:
Cassandra's quote about death is from Julius Caesar, Act II Scene 2, spoken by Caesar before he leaves his house and is assassinated. Cassandra has spent most of her lifetime with a tumor she knows will eventually kill her, and which she once called her "death".
Jake's quote about knowing oneself is from King Lear, Act I, Scene 4. Saliently, it is spoken by a character who, like Jake, is trying to disguise his true identity.
Ezekiel's quote is from I Henry IV, Act I, Scene 2. It is spoken by Prince Hal to explain his plan to exhibit bad behavior before he becomes Henry V, to improve his overall reputation with his subjects. This is a clue to Ezekiel's own inner character - though he is frequently self-absorbed and self-serving, he can become heroic when the situation calls for it.
Cassandra's quote about death is from Julius Caesar, Act II Scene 2, spoken by Caesar before he leaves his house and is assassinated. Cassandra has spent most of her lifetime with a tumor she knows will eventually kill her, and which she once called her "death".
Jake's quote about knowing oneself is from King Lear, Act I, Scene 4. Saliently, it is spoken by a character who, like Jake, is trying to disguise his true identity.
Ezekiel's quote is from I Henry IV, Act I, Scene 2. It is spoken by Prince Hal to explain his plan to exhibit bad behavior before he becomes Henry V, to improve his overall reputation with his subjects. This is a clue to Ezekiel's own inner character - though he is frequently self-absorbed and self-serving, he can become heroic when the situation calls for it.
When they are talking with Shakespeare, back in time, about their 'weird' accent, Rebecca Romijn said in passable Dutch "We zijn echte kaaskoppen, hoor!" (We are real 'cheeseheads'). Explaining they are from Flanders (now in Belgium, then in the Spanish Netherlands), although she spoke modern Dutch from the Netherlands. Rebecca Romijn is familiar with the language through her Dutch father and maternal grandfather.
The location where Prospero and Moriarty talk early in the episode was filmed in the International Rose Test Garden in Portland, OR.