I think Episode which 4-24 aired on May 19, 2011 The Roomate Transmorgrification was very disappointing. Even if Raj and Penny didn't have sex I think the whole situation was very bad for Penny's character and it would have been best if they didn't let it happen.
Did anyone else notice that Penny's Old apartment must be over the Street in the front? If you follow the front door and the stairs up to her apartment the front door and the door into her old apartment are in the line with each other vertically or her door is directly above the front door. Since the front door opens up to the sidewalk and the street that would make her apartment and all the others below hers having the overhang the sidewalk and street. Also when the show the roof no overhang exists.