According to Jim - Pregnancy Brain

Seizoen: 7 - Aflevering: 11 / 157 - Eerst uitgezonden: 11 maart 2008 - Episode ID: 5816

Jim finds a way to use Cheryl's forgetfulness (a.k.a. "the pregnancy brain") to his advantage by trying to convince her that it was her idea to turn the basement into a media room instead of a room for Ruby and Gracie.