Simon Helberg stars as Howard Wolowitz, the only one of the nerds that is not a doctor. He is an engineer at Caltech and is friends with Leonard and Sheldon and frequently is over at their apartment. Wolowitz mostly goes by his last name and still lives with his mother.
Most jokes with Wolowitz revolve around his failed attempts at womanizing, though he was given a girlfriend, Bernadette, in season three.
I don't like to kiss and tell, but somebody made it to eighth base!Wolowitz
Bernadette: They throw an actual ball, you were throwing air at a tv.
Howard: For your information, I also threw Leonard a high five.