Season 3, Episode 7 - The Guitarist Amplification
Aired November 9, 2009
When Penny invites Justin, an old boyfriend, to stay at her apartment for a weeks, it sparks an argument between her and Leonard. Their fighting makes Sheldon uncomfortable as it reminds him of his parents' arguments.
Season 4, Episode 2 - The Cruciferous Vegetable Amplification
Aired September 30, 2010
When Sheldon gets worried he will not live long enough to download his conciousness into a robot, he begins making changes to extend his life. After failed attempts at eating healthily and exercising, Sheldon chooses to speed up the change to being a robotic lifeform by ensconcing himself in his room and living life through a virtual presence device.