This is a scene from the 5/17/10 episode of The Big Bang Theory. Yes, that's Mayim Bialik guest-starring in the sitcom.
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Judy Greer guest starred on The Big Bang Theory as Dr. Plimpton, a famous physicist that Sheldon invites to spend the weekend at the place.
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Penny returns Sheldon to Leonard after their trip to Disney Land. The couple is sharing custody over the nerd.
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Sara Gilbert is seen here on The Big Bang Theory. She plays the character of Leslie.
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This is a photo from the episode "The Wheaton Recurrence." There's really not much to say about it, is there?
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A picture after Wil Wheaton just bowled as Sheldon prepares to counter.
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Penny and Leonard go bowling and Leoanrd sure does seem to be celebrating something.
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Wil Wheaton calls out Sheldon as the two of them meet in the bowling alley.
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TBBT Quotes

Penny: Hey, Sheldon, did you change your Wi-Fi password again?
Sheldon: Yes, it's "Penny, get your own Wi-Fi." No spaces.

Sheldon: Why do you have the Chinese character for "soup" tattooed on your right buttock?
Penny: It's not "soup," it's "courage."
Sheldon: No it isn't. But I suppose it does take courage to demonstrate that kind of commitment to soup.
Penny: How'd you see it? You said you wouldn't look.
Sheldon: Sorry. As I told you, the hero always peeks.