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THE EPISODE TITLES
"The Pancake Batter Anomaly." "The Panty Piñata Polarization." "The Bath Item Gift Hypothesis." "The Dead Hooker Juxtaposition.""The Creepy Candy Coating Corollary." "The Pants Alternative." Who says science isn't fun?
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Halloween comes but once a year, but the BBT guys are no strangers to fabulous costumes. The episode where they all dressed as the Flash was priceless ("We could walk behind each other all night and look like one person going really fast!"), but the guys have donned everything from Frodo outfits to goth garb, with a memorable turn as famous superheroines.
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SHELDON'S SPOCK OBSESSION
An ultra-refined sense of logic that often butts up against human emotions? Gee, wonder what Dr. Cooper sees in his half-Vulcan hero. Sheldon's devotion was in full force in one of the show's best episodes, ''The Bath Item Gift Hypothesis,'' when Penny gave him a napkin used by Leonard Nimoy himself. ''All I need is a healthy ovum, and I can grow my own Leonard Nimoy!'' he squealed, before giving Penny the craziest gift of all: an actual hug.
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The guys' goofy enthusiasm for all things game-oriented, including but not limited to Klingon Boggle and "three-dimensional chess," brings out the best in the characters. Remember, scissors cuts paper, paper covers rock, rock crushes lizard, lizard poisons Spock, Spock smashes scissors, scissors decapitates lizard, lizard eats paper, paper disproves Spock, Spock vaporizes rock, and rock crushes scissors.
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Sara Gilbert will always be Darlene in our hearts, and her reunion with Johnny Galecki is one of the secret little joys of the show. Well, that and Leslie's endless loathing for Sheldon.
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Every hero needs a worthy nemesis. And Sheldon's is geek idol Wil Wheaton. Perfect.
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Sheldon craves and experiences comfort in strange but real ways, and when he's sick, he likes to hear a little song called "Soft Kitty." Penny's obliged him on a few occasions, but the pièce de résistance in the "Soft Kitty" collection was when Penny got Sheldon to sing it for her in "The Adhesive Duck Deficiency." Or when the show's cast and crew sang the song to wish Kaley Cuoco a speedy recovery from her broken leg.
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BILL PRADY'S TWITTER
The BBT's executive producer tweets up a storm, posting backstage photos and insider info. (''On set with Katee Sackhoff and George Takei. @JaneEspenson came to visit. #nerdsplosion.'')
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Who doesn't like to punctuate their jokes with a snappy catchphrase?
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Sheldon's mom (Laurie Metcalf, bottom) is a Bible-toting Texan, while Leonard's (Christine Baranski) is a chilly ultra-academic scientist...who planted a big smooch on Dr. Cooper while she was in a drunken state. Ah, mommy issues.
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DRUNK RAJ, DRUNK SHELDON
What happens when nerds go wild? Amazing, amazing things. Raj can only converse with females if he's hitting the sauce. And Sheldon? Well, get a few Cuba Libres in the guy and he turns into the Piano Man — or even better, just drops trou. Is it any wonder Jim Parsons won his Emmy for the episode where Sheldon got bombed before giving a speech?
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RAJ AND WOLOWITZ
One can't speak to women, and the other...well, can't really speak to women either. The central bromance of the series veers from snide to sensitive and back, usually within the span of a few lines.
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WOLOWITZ'S AND SHELDON'S WARDROBES
From Sheldon's geeky T-shirts to Wolowitz's extreme color palette (not to mention passion for prints) to Penny's perky pjs, the show is basically a mini fashion revolution. Viva la funky duds!
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LEONARD AND PENNY
Talk about beauty and the geek. The two toed a will-they-won't-they line for much of the series, and then went for it — and then broke up. And then sort of went for it again. And then sort of broke up. C'mon, you two!
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SHELDON AND PENNY
Sheldon may have found a companion in Amy Farrah Fowler, and Penny may be star-crossed with Leonard. But we don't care: These two are the central couple on the show, heaping sarcasm and zingers on each other while also lending support and kindness in the only ways they know how.