Watch The Big Bang Theory Season 3 Episode 15: The Large Hadron Collision Online

	IMDB Rating: 8.2/10 from 1,130 votes
	Release: 2010 / The Big Bang Theory / Season 3 / Episode 15
	Genre: Comedy
	Director: Mark Cendrowski
	Stars: Johnny Galecki, Jim Parsons, Kaley Cuoco-Sweeting
	Synopsis: Valentine's Day is approaching. Leonard thinks he's hit some good luck in that he has been asked to attend a conference and view the Hadron super collider in Switzerland during Valentine's. He's allowed to bring a guest with him which he has chosen to be Penny. There, the two can have a romantic first Valentine's Day together. This decision doesn't sit well with Sheldon who has always dreamed of seeing the collider. Sheldon does whatever he can to make Leonard change his mind, including reminding him of their documented roommate agreement. But the harder Sheldon tries to convince Leonard to change his mind, the more Leonard seems to resist. But outside forces may end up deciding for Leonard who will accompany him to Switzerland.