The cast in real life.
The cast obviously has there own lives besides on the show, so here's some info on them. Sheldon is played by Jim Parsons, an interesting fact about him is that in real life, he is gay, or homosexual. Howard is played by Simon Helberg, something interesting about him is he is only 5 foot 4 inches, and earned a black belt in karate at age 10. Penny is played by Kaley Cuoco, as a child, she was a nationally-ranked amateur tennis player, but gave up at age 16. Raj is played by Kunal Nayyar, something you probably don't know is that he married Miss India 2006 winner, Neha Kapur. Leonard is played by Johnny Galecki, not only has he dated Penny (Kaley Cuoco) in the show, but they have admitted to dating in real life in the past! The oldest member is Jim Parsons, who is currently 40 years old. The youngest member is Kaley Cuoco, who is 27 years old. Everyone else is inbetween, Kunal and Simon are both 32 years old, and Johnny Galecki is 38 years old.
Sources: google.com
google.com/images
http://en.wikipedia.org/wiki/The_Big_Bang_Theory
google.com/images
http://en.wikipedia.org/wiki/The_Big_Bang_Theory