6 Facts You Didn't Know About 'The Big Bang Theory'
5 Of 6 Unaired First Pilot
In an unaired first pilot, Amanda Walsh plays Penny's character, at the time named Katie. Katie is more sexual and raunchy in this pilot than Penny is after Kaley Cuoco took on the character. The test audience did not like Amanda Walsh's version of Penny, feeling overprotective of the guys.
6 Of 6 The Legend Of Soft Kitty
"Soft Kitty" is a adapted version of "Warm Kitty," a children's song by Edith Newlin. Bill Prady came up with the adaptation of this song that sooths Sheldon throughout the show. A teacher from his daughter's preschool had heard it in Australia and taught the kids.