Watch The Big Bang Theory Season 4 Episode 18: The Prestidigitation Approximation Online

	IMDB Rating: 8.3/10 from 1,182 votes
	Release: 2011 / The Big Bang Theory / Season 4 / Episode 18
	Genre: Comedy
	Director: Mark Cendrowski
	Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco-Sweeting
	Synopsis: Priya and Leonard's relationship has gotten to a serious stage where Leonard is wearing the clothes that she picks out for him and is trying to wear contact lenses on her suggestion, even though he can't see with them on. As his serious girlfriend, Priya asks him for a big favor: to stop being friends with Penny. She feels uncomfortable having one of his ex-girlfriends be such a big part of his life. So later, when Priya asks him if he's "talked" to Penny, he doesn't tell the complete truth. How long can Leonard get away with this little white lie before he really has to make a decision between Priya and Penny, especially as Priya is thinking about relocating to southern California for good? Meanwhile, Howard performs a card trick which confounds his friends. Sheldon states that he doesn't care about the trick, but it's obvious that not knowing how the trick is done is killing him.