8. The show was titled “Lenny, Penny and Kenny”, and had actress Amanda Walsh playing Kaley Cuoco’s role.
‘Penny’ was initially named ‘Katie’, who was portrayed as a tomboy with a tough exterior. The character didn’t sit well with the pilot’s studio audience and was later changed to the Penny we know now. Sheldon was also differently modeled in the unaired pilot episode; he wasn’t as condescending as he is now, understood sarcasm and had even engaged in sexual relationships.
9. As of Season 6, episode 21, Sheldon delivered the most number of lines in the show.
6887 in all, to be very specific. Bernadette and Amy came in second-last and last with 1154 and 977 lines each.(source)
10. Nobody knows what Penny’s last name is, and she is the only character whose mother hasn’t been introduced in the show.
11. Lucy, Raj’s girlfriend, was nearly cast as Amy. Kate Micucci almost bagged the role, but wasn’t quite right for the part as she was too ‘awkward’ to play Sheldon’s love interest. The writers kept her on the list, however, and brought her back as Raj’s timid-but-endearing girlfriend.
12. The elevator and staircase scenes are filmed on the same floor. They are painstakingly remodelled inch-by-inch to make it appear as though the characters are climbing or descending more than one flight.
13. The origin of the word “Bazinga!” was a grapefruit.
Before its debut in the season two finale, it was part of a silly backstage prank involving an old grapefruit in the writers’ room. Stephen Engel used the word as a way of saying ‘gotcha!’ whenever Bill Prady opened it up.(source)
14. Raj, Leonard and Howard discussed Mayim Bialik even before she was on the show.
While thinking of a replacement for Sheldon on their Physics team, Raj says, “You know who’s apparently very smart, is the girl who played TV’s Blossom. She got a Ph.D in neuroscience or something.” Is that super meta or what.