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Watch The Big Bang Theory Season 3 full episodes online, free and paid options via our partners and affiliates.
Blossom alert! Former sitcom star Mayim Bialik guest stars on the season finale as a potential love interest for Sheldon.
Leonard tells Penny the story of how the apartment elevator broke through a series of flashbacks.
Sheldon has a female physicist, Dr. Plimpton (Judy Greer) spend the night at the apartment.
After Penny and Leonard break up, Sheldon goes behind Leonard's back to hang out with Penny.
Sheldon goes up against his nemesis, Wil Wheaton at the bowling alley while Leonard and Penny have their own fight.
When Sheldon is forced to give an acceptance speech for an award he received, he must overcome his stage freight.
When the guys buy a Lord of the Rings ring from a garage sale, they all begin to covet their precious.
Sheldon misses his chance to meet comic book creator Stan Lee when he's stuck in traffic court over a ticket that Penny got him.
When Leonard is giving a plus one to go to Switzerland to see the Large Hadron Collider on Valentine's Day, Sheldon tries to convince Leonard to take him over Penny.
Sheldon gets a job at the Cheesecake factory to help his solve a theory; Leonard and Wolowitz steal Raj's idea for a double date.
When Leonard and Sheldon's apartment gets robbed, their friends help them devise a security system.
Sheldon and Raj attend a university mixer where Raj meets Abby (Danica McKellar); Leonard is upset to find out that Penny believes in psychics.
Leonard's mother, Beverly (Christine Baranski), is back and Leonard is upset to find out she's getting divorced and told Sheldon, not him.
Penny seeks Sheldon's help to better understand Leonard's work; Wolowitz gets jealous when Leonard and Bernadette become friends.
When Kripke embarrasses Sheldon on NPR, he swears revenge; Wolowitz is scared to commit to Bernadette.
When Leonard, Raj and Wolowitz go camping, an injured Penny must rely on Sheldon for help.
When Penny's musician ex-boyfriend wants to crash on her couch, Leonard and Penny fight and Sheldon tries to stop them.
Leonard gets tutored in football by Sheldon; a kite flying mishap causes a fight between Wolowitz and Raj
Sheldon goes up again the Star Trek actor, Wil Wheaton; Wolowitz wants Penny to set him up with one of her friends
Desperate to avoid going back to India, Raj considers a job working for Sheldon; Howard becomes a third wheel to Leonard and Penny
Howard takes Raj with him to the Goth dating scene; Sheldon uses chocolate as part of his behavioral experiment on Penny.
Leonard and Penny try and make things not awkward after their hookup; Sheldon and Wolowitz bet their best comic books on a bet to determine the species of a cricket
Sheldon runs to his mother when he learns the gang messed with her arctice expedition's data; the guys go chasing after him with Leonard sacrificing his chance with Penny.