|The series was originally supposed to debut in the 2006-2007 CBS lineup, but ended up being delayed until the 2007-2008 fall lineup.|
|Series creators Chuck Lorre and Bill Prady also work together on Two and a Half Men.|
|Both Amanda Walsh and Iris Bahr were originally cast in the role of Penny, who was originally named Katie and then Gilda.|
|Johnny Galecki (Leonard), Sara Gilbert (Leslie Winkle) and series creator Chuck Lorre all worked on Rosanne.|
|All episodes (except for the pilot) have the same episode title formatting, which consists of three parts:|
1. The word "The".
2. Some word(s) that describe something featured in the episode.
3. A scientific word that describes the previous description.
An example is episode 1x02: "The Big Bran Hypothesis", with "The", two words describing Sheldon's action of switching cereals (big bran) and a scientific word, "Hypothesis".