The Big Bang Theory

It's a television series created by Chuck Lorre and Bill Prady. It's directed by James Burrows and Mark Cendrowski.

Plot:

It is about two men that are really smart, one an applied physicist (Leonard Hofstadted) and the other a theoretical physicist (Sheldon Cooper), who live across the hall from an attractive blonde waitress and aspiring actress (Penny).

Starring:
Johnny Galecki
Jim Parsons

Kaley Cuoco
Simon Helberg
Kunal Nayyar
Sara Gilbert 

Melissa Rauch

Catchphrases and gags:

The show has many catchphrases, mainly stemming from Sheldon. They include, "You're in my spot" and "Bazinga!"

A running gag is when Sheldon knocks on other characters' front doors, most often Penny's: knock-knock-knock "Penny," knock-knock-knock "Penny," knock-knock-knock "Penny".

Videos:

http://www.youtube.com/watch?v=l2hIIvF5gJI

http://www.youtube.com/watch?v=d-jnyvjtdfg