Rajesh "Raj" Koothrappali
Kunal Nayyar stars as Rajesh Koothrappali, an Astrophysicist that works with Sheldon and Leonard at Caltech. He is best friends with Wolowitz and lives in an apartment by himself. Rajeesh is from India and communicates with his parents back at home via video conferencing software.
Rajeesh is a bit of a celebrity after he was named in People's "30 Under 30." Rajeesh has major social anxiety and can only talk to women under the influence of alcohol.
Raj: Well, to paraphrase Shakespeare: It's better to have loved and lost than to stay home every night and download increasingly shameful pornography.
Penny: Oh... you poor baby.
Raj: What's wrong with me, Penny?
Penny: Nothing, nothing. You know, if we weren't friends - and you hadn't brought up that creepy pornography story - I'd be on you like the speed of light squared on matter to make energy.
Raj: Hey, you totally got that right. E = MC squared.
Penny: I listen. I have no idea what it means, but I listen.
Sheldon: I recently read that during World War Two, Joseph Stalin had a research program to create supersoldiers by having women impregnated by gorillas.
Howard: What a sick use of science.
Raj: Hey, as long as the baby's healthy.
Amy: I wonder if Stalin considered any other animals.
Leonard: Hippos are the deadliest creature. A half-human, half-hippo soldier would be pretty badass.
Howard: Yes, but when they're hungry-hungry, you can stop them with marbles.
Sheldon: Yeah, the correct animal for interspecies supersolider is koala. You would wind up with an army so cute it couldn't be attacked.