The hitherto unseen characters of Joyce Kim, a North Korean spy who dated Leonard, and the pairs' original neighbor, Louie/Louise, the "two hundred pound transvestite with a skin condition" are seen.
The references to B-Stoff and C-Stoff on Sheldon's white board represent two types of rocket fuel used by the Germans during World War II. They were used in the the V-2 and Me-163 (with T-stoff) respectively.
Sheldon mentions the (then new) TV series "Firefly (2002)" and predicts that it will go on for years. This is a joke, as "Firefly" was infamously canceled after just one season (which Sheldon had acknowledged in The Large Hadron Collision (2010)), although the show was followed up by the full-length movie Serenity (2005).
In this episode we learn that Sheldon and Leonard's apartment has a flag. It bears a logo identical to that of Löwenbräu beer. The same or similar lion has been used on other flags, such as:
- The coat of arms of Bulgaria;
- The official flag of the city of Leeuwarden in The Netherlands between 1750 and 1947;
- The commune of Savagnier in the canton of Neuchatel in Switzerland;
- It is almost identical to the flag of the city of Lviv in Ukraine.
Most of the characters dress as though they were in the '80s during the flashback scenes, even though they take place in 2003.