There were plans to bring the Rock Band series to Japan with a Japanese exclusive game called Rock Band Japan. This idea was scrapped when the development team found it difficult to license most Japanese music, coupled with the fact that most Japanese families tend to not make a lot of noise in their homes due to the space limitations.
Harmonix specifically requested Devo's song "Through Being Cool" for Rock Band, which Devo founder, Mark Mothersbaugh, found "kind of odd because it's all synth solos." To make it relate to the game better, they re-recorded the song to replace all the synth leads with guitar leads.
In the Rock Shop available in the Rock Band games, there's a purchasable character named "Doctor What" who is a parody of the character 'the Doctor' from the science fiction series "Doctor Who." He is seen wearing a long jacket and scarf which are two pieces of clothing often associated with the character.
When Harmonix was secretly developing the Rock Band Network (A network that allows artists to make their music playable in Rock Band games), they gave it the unofficial code name "Rock Band: Nickleback" to avoid attracting attention. They thought adding "Nickelback" to the title would deflect any and all curiosity, ensuring it wouldn't be leaked.