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.
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.
Penny returns Sheldon to Leonard after their trip to Disney Land. The couple is sharing custody over the nerd.
Sara Gilbert is seen here on The Big Bang Theory. She plays the character of Leslie.
This is a photo from the episode "The Wheaton Recurrence." There's really not much to say about it, is there?
A picture after Wil Wheaton just bowled as Sheldon prepares to counter.
Penny and Leonard go bowling and Leoanrd sure does seem to be celebrating something.
Wil Wheaton calls out Sheldon as the two of them meet in the bowling alley.

TBBT Quotes

Sheldon: I recently read that during World War Two, Joseph Stalin had a research program to create supersoldiers by having women impregnated by gorillas.
Howard: What a sick use of science.
Raj: Hey, as long as the baby's healthy.
Amy: I wonder if Stalin considered any other animals.
Leonard: Hippos are the deadliest creature. A half-human, half-hippo soldier would be pretty badass.
Howard: Yes, but when they're hungry-hungry, you can stop them with marbles.
Sheldon: Yeah, the correct animal for interspecies supersolider is koala. You would wind up with an army so cute it couldn't be attacked.

Raj: Well, to paraphrase Shakespeare: It's better to have loved and lost than to stay home every night and download increasingly shameful pornography.
Penny: Oh... you poor baby.
Raj: What's wrong with me, Penny?
Penny: Nothing, nothing. You know, if we weren't friends - and you hadn't brought up that creepy pornography story - I'd be on you like the speed of light squared on matter to make energy.
Raj: Hey, you totally got that right. E = MC squared.
Penny: I listen. I have no idea what it means, but I listen.