The Parallel Universe Box.
The Parallel Universe Box was an invention accidentally created by Professor Hubert J. Farnsworth. Within the box was a parallel universe, inside which were alternate colour versions of the Planet Express crew. According to the episode, The Farnsworth Parabox, the only differences between the universes are coin flips, which apparently have decided the majority of Planet Express' decisions and the colours of people. The box is used in conjunction with the Alternate Universe Box.