The late Dr. David Saltzberg is mentioned as a key character in the escape room that Emily, Raj, Leonard and Amy attend. In reality, Dr. David Saltzberg is the science consultant for the show.
The flight number Bernadette gives the baggage attendant, '816' is a reference to the episode the show is on, season 8 episode 16.
While trying to solve a mystery in the escape room, Amy and Emily are dressed like Velma and Daphne (Scooby-Doo) respectively.
Molly Morgan (Hostess) played 'Bethany,' one of the two Goth girls chatted up by Howard and Raj, in the season 3 episode The Gothowitz Deviation (2009).
It is revealed that Sheldon is a Pisces because the events shown take place on his birthday. The episode was first broadcast on 26th February 2015, which does indeed fall within the astrological sign of Pisces.