In this episode, Chandler becomes better at a Ms. Pacman game, and his hand is misshapen. Before he reveals that his hand is distorted, he points to the screen, and his hand is just fine. However, after he shows Monica his hand, it won't move no matter what.
In reality, Ross's graduate seminar would only involve a few students, not a packed classroom. There is no such thing in graduate school as a bell ringing at the beginning and end of a class. And there is a 15-minute grace period which means if Ross was "a lot late" for the class, his students would have gone home a while ago.
When Monica unwraps Phoebe's wedding gift, she is extremely excited and suggests they put it in the guest bedroom. However, in TOW Ross's Denial (#6.3) when Chandler suggests turning the spare room into a game room and buying arcade games Monica is vehemently against the idea.