Counting each of the four movies as four separate episodes for a total of sixteen, this is the 100th episode of the series. This is referenced several times in the episode, most notably with the 100th delivery of Planet Express.
During Leela's tour of the sewer we see the West Side Pipeway. The design for that was taken from Fritz Lang's 1927 movie 'Metropolis.'
A can of "Angry Norwegian" anchovies can be seen by the Land Titanic. Fry and the Planet Express crew had previously eaten the last known anchovies in existence earlier in the series.
When the mutant version of Devo yells "Are we not men yet?" This is a reference to the Devo album: "Q: Are We Not Men? A: We Are Devo."
Before the guests arrive, Bender adds a drop of "Michael Collins Mix" to the punch for his party. Michael Collins was the third (lesser known) crew member of Apollo 11, along with Neil Armstrong and Buzz Aldrin. He piloted the command module that orbited the moon while Armstrong and Aldrin became the first two men to walk on the surface.