In chapter 23, the Commander has summoned Offred to meet him in his study.
Offred is afraid. She doesn't want to be caught because she knows that Serena won't be merciful in doling out punishment. Yet refusing such a powerful man is out of the question.
On the other hand, Offred is also intrigued by the Commander's request. She thinks that he wants something from her. This "want" may reveal what the Commander's weakness is, and it may be something that Offred can use to gain leverage against him.
Therefore, she meets him in the study. When she enters, she sees the Commander striking a "classic" pose by the fireplace. There's no fire in the fireplace. Under the circumstances, the pose is ridiculous. Offred is terrified and knows that this isn't a casual date.
What she does notice, however, is that the walls of the study are lined with bookcases. Here in the study, there are no locks and boxes. Books sit out in the open, ready to be picked up and read. Offred now understands why the study is a forbidden room.
Meanwhile, the Commander pulls out a chair for her. She sits down and notices that he isn't reaching out to touch her in inappropriate ways. Instead, he sits down behind his desk.
Then, the Commander makes a strange request: he asks Offred to play a game of Scrabble with him. Upon hearing his request, Offred has to stifle her laughter. Before life changed, Scrabble used to be popular with old people and teenagers.
Offred can't imagine why the Commander would want to play this game with her. However, she notes that the game has now become forbidden. The Commander can't play Scrabble with his wife; to do so would compromise his authority and influence.
From the text, we get the idea that the Commander is just as tired of the restrictions as everyone else. He wants to live a normal life. Offred notes the irony of the Commander's act of rebellion.