The original reason for Sheldon's ongoing insults to Howard is finally revealed.
The table that Leonard and Penny bought in the previous episode is gone in this episode, implying that Sheldon finally got his way and they got rid of it.
This is the first time that Sheldon does his signature three-time knock for Howard (even if he isn't knocking a door but Howard himself).
First appearance of Emily Sweeney (Laura Spencer). She is the second girl called Emily whom Raj will date, after Emily from The Wiggly Finger Catalyst (2011).
Raj says that he hasn't had sex in two years. The last time was probably in The Wiggly Finger Catalyst (2011) two seasons ago, when he had a brief relationship with a girl called Emily (in his own words, she gave him "the best [sex] I ever had"). Since then, Raj has only been with Lucy in season 6, but they only "hugged twice, kissed once, and a handshake full of sexual innuendo", as later revealed in The Indecision Amalgamation (2014).