In his DVD commentary, writer Drew Z. Greenberg says that in his original conception of Willow's confrontation with the homophobic men at the Bronze, he intended for Willow to cast a spell on the men so that they couldn't stop kissing each other. Joss Whedon vetoed the idea because he did not want to portray people's sexual orientation as changing in an instant and he did not want to portray same-sex kissing as a punishment.
The statue of Janus that Ethan Rayne used to turn everyone into their Halloween costumes in S2's Halloween (1997) can be seen on top of a shelf in the Magic Box behind Buffy. This must be a replica, as Giles previously smashed it.
Amy says she wants to ask Larry to the prom, only to be informed by Willow of his death (and that he was gay). Larry was killed by Mayor Richard Wilkins in the Season 3 finale Graduation Day: Part 2 (1999), when he broke his neck with a tail whip.
Willow's comment to Amy about sewing her name in her clothes before doing any forgetting spells references the previous episode, where ID and clothing labels told most of the gang who they were.
A brief clip from this episode is included in Star Wars Spoofs (2011), a compilation special feature on Bonus Disc 3 of the Star Wars The Complete Saga bluray release.