Rating: 7.56 million
This episode is sometimes referred to as "The Shiksa Indeterminacy".
This is the first episode in which we get a glimpse of Sheldon in his office at the university.
It's revealed that Sheldon is a fraternal twin.
This makes the only episode (so far) where we get a glimpse of Sheldon's twin sister although in Season 7 it's revealed that since her appearance here she has gotten married and given birth to a child.
Missy's Texas accent seems to come and go as it pleases. When we first meet her she has no accent, however, in her following scene, she now sports a very noticeable accent. Throughout the rest of the episode she might have an accent in one scene but not in another.
Sheldon's sister Missy visits him in order to have him sign papers regarding their late father's estate which leads the viewer to deduce that he passed away recently. Yet in a Season 7 episode Sheldon specifically states that his father died when he (and twin Missy) were 14.