The Big Bang Theory's Unaired Pilot, as it is generally known on the Internet, refers to the original Television pilot|pilot made for the 2006–2007 season that was not picked up by the television network|network, thus it was never aired.

Why do all first episodes called pilot?

1 Expert Answer

The first episode of a series is called a pilot because it leads what is to follow, and establishes its tone and pace.

Was Sherlock filmed twice?

The pilot episode of BBC's Sherlock, "A Study in Pink", was shot twice, and the first version never aired – here's what happened and what changed. BBC's Sherlock was very well received from the beginning, and that's all because the pilot episode was reshot – here's what happened.