: In the opening scene, the gang is watching the 1966 How the Grinch Stole Christmas! . Funnily enough, guest star Christine Baranski also appeared in the 2000 live-action film adaptation.

: Leonard is horrified to discover that Sheldon and Beverly have been in regular contact. Sheldon has known for weeks about major family updates that Leonard was kept in the dark about, including his parents’ pending divorce , the death of the family dog , Mitzy, and Beverly’s recent surgery .

: Sheldon objects to traditional Christmas decorations, instead hanging a bust of Sir Isaac Newton on the tree because Newton was born on December 25th, unlike the historical figure typically associated with the holiday.

: Sheldon jokes about leaving the Enterprise in a shuttlecraft to a planet he rules, "Sheldon Alpha 5," a nod to the planet Ceti Alpha 5 from Star Trek II: The Wrath of Khan . Critical Reception