500 Keys/References

References/Trivia

Cultural References

When Lisa finds the hidden classroom:
- She observes that the stage is set for a production of the play Endgame by Samuel Beckett.
- Lisa discovers that the objects in the classroom appear real, but are revealed to be fakes on closer inspection. Near the end of 2001: A Space Odyssey, astroanut David Bowman finds himself in a similarly fabricated hotel room.
- Lisa returns to the classroom with a huge crowd and school newspaper reporters in tow, only to find nothing but bookshelves, similar to the Geraldo Rivera special The Mystery of Al Capone's Vaults, where after a huge media buildup the vault was anticlimactically discovered to be empty except for dirt and debris.
When Bart gets onto the window washing platform, the music playing is an inversion of the title theme from Peter and the Wolf.
During the blimp pursuit (Chief Wiggum and Lou in the Springfield Police Department blimp chasing Homer in the Duff Beer blimp:
- Homer eludes Wiggum by suddenly climbing and flying over a billboard advertising a Cirque du Soleil performance titled "Zoomanity".
- Wiggum crashes into the billboard and cries "Oh, the zoomanity!" as his blimp catches fire, referencing the Hindenburg disaster.

The chalkboard gag is a reference to Kristen Schaal's name being misspelled as "Kristen Schall" in the closing credits of "Homer Scissorhands".
In the band room scene of the opening sequence, Lisa plays a violin instead of her saxophone.