At the Van Nuys Comicon, the table to Penny and Leonard's left is that of David Gerrold. He is a Hugo and Nebula award-winning American science fiction screenwriter and novelist. He wrote the "Star Trek" story "The Trouble with Tribbles", as well as dozens of novels, short stories, and TV scripts. He seems to be selling Tribbles at his table.
This is the first episode where Bernadette starts to wear jeans and a blouse instead of a floral dress and a cardigan.
The credits on the posters for Serial Ape-ist and Serial Ape-sit 2 list the director's credits to Nikki Lorre, who is the daughter of Big Bang Theory creator Chuck Lorre. This implies that the male British director of the sequel who fired both Penny and Wil Wheaton in The Gorilla Dissolution (2014) was eventually fired himself, or quit the movie.
When discussing their party, Sheldon says "I hope it's not a West Coast party, 'cause according to the man on the radio, a West Coast party don't stop." He is referencing lyrics to the song "1, 2, 3, 4 (Sumpin' New)" by Coolio.
Leonard says that he once paid $20 for Theo Sassler's autograph, even though he didn't know who he was (he just liked the name). For the record, there is no celebrity named Theo Sassler in real life, it was just an invented name for the script.