Sheldon's Bedroom or Rajesh's New Bedroom is a secondary setting in The Big Bang Theory. The bedroom is supposedly meant for Sheldon and his eyes alone, but his friends usually Leonard and Penny, and his family members Mary Cooper and Missy Cooper have been there.
In the series
This room isn't shown much in the series, but it is used as a private place where any of Sheldon's friends discuss issues with him. At one time, Sheldon is too paranoid to used his bedroom door, so he used his bedroom window to get to Leonard's bedroom on the window ledge. Sheldon also lays on his bed whenever he is frustrated, sulking or humiliated at times.
In The Cruciferous Vegetable Amplification, Sheldon used his bedroom as his base to keep himself from the outside world to prevent any further discomfort and replaces himself with a virtual presence.
Several days and weeks after Sheldon has moved out, the bedroom became vacant, until Raj is given the bedroom when he stays at the apartment after being evicted from his old apartment, due to Raj cutting himself off from his family.