| In the first season Futurama episode "A Big Piece of Garbage" Fry was smelling his way through the solar system with Professor Farnsworth's smelloscope, a telescope-like device that allows the user to smell the unique scent of each celestial object in the universe. Saturn, for example, smells like pine needles.
While using the smelloscope Fry made the comment "Just don't make me smell Uranus." Nobody understood the humor in the comment, and the professor explained that in 2261 astonomers renamed Uranus to end that stupid joke once and for all. What'd they rename it to? Urectum.
On the Season 1 DVD audio commentary for this episode the production team joked that the renaming of Uranus assured that the Planet Express crew could never visit there. | 
