The fifth time in the series that Sheldon changes the Wi-Fi password: in The Panty Piñata Polarization (2008), Sheldon cut Penny off the internet for "piggy-backing upon our Wi-Fi" (password not specified); in The Thespian Catalyst (2011), he changed the password to 'pennyisafreeloader'; in The Roommate Transmogrification (2011), it was changed to 'pennygetyourownwifi'; in The Speckerman Recurrence (2011), it became 'pennyalreadyeatsourfoodshecanpayforwifi'; and here, he changes it to 'hahahanowivegotyou'.
The salt & pepper shakers in Howard and Bernadette's house are the same as the ones found in Leonard and Sheldon's apartment.
Only appearances of the interior views of the living room "fourth" walls in both apartments 4A & 4B.
The guest star, Christopher Lloyd, is well known for his portrayal of Doc Brown in the Back to the Future trilogy. Sheldon dresses as Doc Brown in season 12's Halloween show, The Imitation Perturbation.